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Selected Publications

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LifeTein® provides custom chemical synthesis, custom peptide synthesis, and custom antibody products and services to support academic institutions, government research facilities, and pharmaceutical and biotech companies locally and worldwide to accelerate the process of biological research. Our practical chemistry often involves molecular interactions in multiple phases beyond gaseous collisions. LifeTein's research and development efforts involve continuous attempts to improve and find alternative peptide synthesis routes and provide guidance on protein structure studies. With the help of LifeTein scientists, our customers have made many breakthroughs and developed many innovations relevant to fields of research including proteomics and cell biology.

Success Stories: References using synthetic peptides and antibodies from LifeTein.

Highlights:

Cell, Volume 159, Issue 4, 6 November 2014, Pages 844–856, A Noncanonical Frizzled2 Pathway Regulates Epithelial-Mesenchymal Transition and Metastasis

Overlapping peptides from LifeTein were used to map the region of Fragment 3 by epitope mapping of anti-Fzd2 antibody. This anti-Fzd2 antibody was found to reduce tumor growth. Peptide library is increasingly used to define antibody epitopes and substrate specificities of protein kinases. For epitope mapping, overlapping peptides are made to span the antigenic protein sequence. The antigenic determinant recognized by a monoclonal antibody can then be screened and defined. The alanine scanning method can also be used to assess that residue’s contribution to antibody binding and to determine which substitutions affect antibody recognition (mutational analysis). Unrelated synthetic peptides can be used to evaluate the antibody cross-reactivity.

Nature Communications, Accepted 02 Aug 2014, doi:10.1038/ncomms5904, An endocytosis pathway initiated through ​neuropilin-1 and regulated by nutrient availability

Biotin labeled peptides were synthesized by LifeTein and conjugated with nanoparticles. A 6-amino-hexanoic linker was added between biotin and peptide to form a flexible space. It was found that a peptide designed for tumour-homing with a carboxy-terminal, basic sequence motif can act as cell penetration peptide to enter tumour tissue. This is a breakthrough for drug delivery into tumours. In addition, this neuropilins mediated endocytosis is distinct from known endocytic pathways. The nutrient regulation of the pathway is a new finding to use of the C-terminal, basic sequence motif pathway in drug delivery.

Nature, Carbonic anhydrases, EPF2 and a novel protease mediate CO2 control of stomatal development, Accepted 06 May 2014, doi:10.1038/nature13452

Synthetic peptides EPF from LifeTein were used for in vitro cleavage. A long peptide of 69 amino acids was used for enzyme cleavage. Other Dabcyl/EDANS-labeled peptides were also used to support the results. The results showed that the EPF2 are converted to an active peptide ligand isoform upon cleavage. EPF2 is essential for CO2 control of stomatal development. The study advances the understanding of how plants perceive and relay the elevated CO2 signal.

Nature Materials, Etchable plasmonic nanoparticle probes to image and quantify cellular internalization, Accepted 14 April 2014, doi:10.1038/nmat3982

Peptides with multiple modifications such as pegylation, biotinylation, fluorescein, and aminohexanic linker were synthesized by LifeTein. The synthetic peptides were attached to nanoparticles as bioactive compounds to cells in vitro and in vivo. The nanoprobes based on etchable Ag cores with synthetic peptides are a powerful tool in studies of targeted uptake and trafficking from a subcellular to tissue level. The FAM-labeled peptides with fluorescent imaging technique in live cells is demanding. However the dye-labeled Ag nanoprobes can be tracked through the cell uptake and intracellular transport process.

Nature Communications, An alternate binding site for PPARγ ligands, 5, Article number: 3571 doi:10.1038/ncomms4571

PPARγ is a target for insulin-sensitizing drugs such as glitazones. Many synthetic ligands can mimic endogenous ligand binding to a canonical ligand-binding pocket to hyperactivate PPARγ. The time-resolved Förster resonance energy transfer (TR-FRET) was used for the ligand binding experiments. FITC conjugated peptides were synthesized by LifeTein. The biotinylated peptides and FITC conjugated peptides were used for the TR-FRET coregulator bind assay. The results showed that alternate site binding can occur when the canonical ligand-binding pocket is bound by an endogenous ligand. The results suggest that allosteric modulators could be designed to fine tune PPARγ activity without competing with endogenous ligands.

Nature, Jia Shen. et al. EGFR modulates microRNA maturation in response to hypoxia through phosphorylation of AGO2. 497, 383–387 (16 May 2013), doi:10.1038/nature12080

LifeTein helped designed and synthesized a series of phosphorylated peptides. Then the peptides were used for phospho-specific antibody productions. The phospo-specific antibodies by LifeTein were confirmed to react with the epidermal growth factor receptor (EGFR). The Hung's lab showed that AGO2-Y393 phosphorylation mediates EGFR-enhanced cell survival and invasiveness under hypoxia. These findings suggest that modulation of miRNA biogenesis is important for stress response in tumor cells.

Supplementary information

Nature Communications., Srinivasan, P. et al. Disrupting malaria parasite AMA1–RON2 interaction with a small molecule prevents erythrocyte invasion. 4:2261 doi: 10.1038/ncomms3261 (2013).

Biotin-RON2, a synthetic biotinylated 42 mer peptide, was synthesized by LifeTein. Synthetic peptides are crucial in the process of understanding protein-protein interactions. Using a high throughput screen method, Prakash Srinivasan assessed the inhibitors that block interactions between AMA1-RON2. He shows that the inhibitor binds to AMA1 and prevents its interaction with RON2. Such inhibitors of merozoite invasion used in combination with existing antimalarials hold great promise as a novel therapeutic approach in the fight against malaria.

Journal of Neuroimmunology, Epstein Barr Virus and Mycobacterium avium subsp. paratuberculosis peptides are cross recognized by anti-Myelin Basic protein antibodies in Multiple Sclerosis patients. Mar. 2014.

Synthetic peptides from LifeTein were used for Epstein-Barr virus studies. It was found that two peptides from EBV and MAP cross-react with a MBP epitope in Multiple Sclerosis (MS). Competitive assay demonstrated that antibodies recognizing EBNA and MAP cross-react with MBP possibly through a molecular mimicry mechanism. EBV and MAP might trigger autoimmunity through a common target.

Acta Diabetologica, Recognition of zinc transporter 8 and MAP3865c homologous epitopes by new-onset type 1 diabetes children from continental Italy. Feb. 2014.

Synthetic peptides from LifeTein were used for diabetic studies. It was found that anti-MAP antibodies against Mycobacterium avium subspecies paratuberculosis (MAP) and ZnT8 epitopes were more prevalent in the sera of new-onset T1D children compared to healthy controls. Addition of anti-MAP antibodies against synthetic peptides by LifeTein to the panel of existing T1D biomarkers should be considered.

Biochemistry, Lobe-Specific Calmodulin Binding to Different Ryanodine Receptor Isoforms, DOI: 10.1021/bi401502x，January 21, 2014.

Some proteins are impossible to be cloned using routine PCR. However these proteins could be synthesized chemically. The Ryanodine receptors (RyRs) Calmodulin (CaM) CaMBD3 wild type and disease mutant proteins were synthesized by LifeTein. The results show that a Ca2+/CaM and apoCaM binding site is the target for malignant hyperthermia and central core disease mutations in RyR1, which affect the energetics and mode of CaM binding.

J Tumor Biology, Brain tumor senescence might be mediated by downregulation of S-phase kinase-associated protein 2 via butylidenephthalide leading to decreased cell viability, 2014，1010-4283.

Anti-FLAG monoclonal antibody was purchased from LifeTein to study the Brain tumor senescence. It was found that BP-triggered senescence in GBM cells is highly associated with its control on Skp2 regulation.

J. Cell Biol., Novel septin 9 repeat motifs altered in neuralgic amyotrophy bind and bundle microtubules, Xiaobo Bai, Jonathan R. Bowen, Tara K. Knox, Kaifeng Zhou, Manuela Pendziwiat, Gregor Kuhlenbäumer, Charles V. Sindelar, and Elias T. Spiliotis, 2013; 203:895-905.

Using synthetic peptides from LifeTein, Xiaobo Bai identified the interactions between septin 9 and microtubules. It was found that the N-terminal domain of SEPT9 contains the novel repear motifs, which bind and bundle microtubules by interacting with teh acidic C-terminal tails of beta-tubulin. The finding provides the first insight into the mechanism of septin interaction with microtubules.

McFadden, Meghan J., "Application of Magnetic “Fishing” and Mass Spectrometry for Function-based Assays of Biomolecular Interactions" (2014). Open Access Dissertations and Theses.Paper 8547.

A series of ligase IV peptide fragments synthesized by LifeTein was used for a competitive displacement assay to probe disruption of X-ray cross complimenting protein 4/XRCC4-interacting region of ligase IV. A short helix was identified and the helix can be used as a more defined target surface for future high-throughput screening and rational drug design. The functional Mass spec-based assays are highly adaptable tools to monitor protein-protein interactions.

Food Chemistry, Xin Huang, Päivi Kanerva, Hannu Salovaara, Jussi Loponen, Tuula Sontag-Strohm, Oxidative modification of a proline-rich gliadin peptide, Volume 141, Issue 3, 1 December 2013, Pages 2011-2016, ISSN 0308-8146

Short peptides are usually synthesized by the liquid phase synthesis. A tripepetide synthesized by LifeTein was used for the metal-catalysed oxidation. α-gliadin, 33-mer (LQLQPFPQPQLPYPQPQLPYPQPQLPYPQPQPF) is a model peptide. This peptide was chosen to be treated in several oxidative systems. Iron-catalysed hydrogen peroxide-induced oxidation of 33-mer showed the greatest modification. Carbonyl groups and dityrosine cross-links were readily formed.

Journal of Insect Physiology, Heather G. Marco, Petr Šimek, Gerd Gäde, Adipokinetic hormones of the two extant apterygotan insect orders, Archaeognatha and Zygentoma, Available online 13 November 2013, ISSN 0022-1910

The Gäde lab is the first lab to report the AKH peptide structures in the primitive insects and the first of any peptide in the Archaeognatha. The anaim- AKH was custom-synthesised by LifeTein. Immunocytochemistry with an AKH antibody shows the intrinsic CC cells of bristletail, firebrat and silverfish.

Biochemistry, Mechanistic Basis for the Potent Anti-angiogenic Activity of Semaphorin 3F, 2013, Hou-Fu Guo , Xiaobo Li , Matthew W. Parker , Johannes Waltenberger , Patrice M. Becker , and Craig W. Vander Kooi, DOI: 10.1021/bi401034q

Neuropilin-1 (Nrp1) binds to VEGF and Sema3. The Kooi lab showed that the C-1 position critically modulates Nrp binding and VEGF inhibitory potency from a previous study published on the Journal of Molecular Biology. Using synthetic peptides from LifeTein, the Kooi group demonstrated that a changed binding motif can have dramatically different potencies. The team suggested that furin processing not only switches Sema3 into an activated form but can also tune potency. The study provides basis for the design of bivalent Nrp inhibitors.

Molecular Immunology, Antigenic epitopes of MAP2694 homologous to T-cell receptor gamma-chain are highly recognized in multiple sclerosis Sardinian patients, Volume 57, Issue 2, February 2014, Pages 138–140

Peptide library is a unique tool to screen the target region. Using a peptide library synthesized by LifeTein, the Sechi lab designed the peptide library spanning MAP2694 entire sequence and used for screening by ELISA. They identified several reactive epitopes. The competitive inhibition assay revealed that the two most recognized epitopes were immunodominant.

J. Biol. Chem., Pre-existent Asymmetry in the Human Cyclooxygenase-2 Sequence Homodimer, Liang Dong, Narayan P. Sharma, Brice J. Jurban, and William L. Smith, 2013; 288:28641-28655.

Anti-FLAG monoclonal antibody was purchased from LifeTein to study the cyclooxygenase-2 (COX-2). It was found that the COX-2 can fold into a preexistent confromational heterodimer. COX-2 half-sites functionality results from COX-2 folding into stable conformational heterodimer.

Cell Stress and Chaperones, Golgi fragmentation induced by heat shock or inhibition of heat shock proteins is mediated by non-muscle myosin IIA via its interaction with glycosyltransferases, A Petrosyan, PW Cheng, 2013, DOI: 10.1007/s12192-013-0450-y

The Golgi apparatus is a highly dynamic organelle. Golgi can undergo fragmentation by heat shock. Pi-Wang Cheng, using synthetic peptides from LifeTein, demonstrated that the fragmentation is mediated by non-muscle myosin IIA (NMIIA) via its interaction with glycosyltransferases. NMIIA is the master regulator of Golgi fragmentation.

Mol. Cell. Biol., CD81 Controls Sustained T Cell Activation Signaling and Defines the Maturation Stages of Cognate Immunological Synapses V. Rocha-Perugini, M. Zamai, J. M. González-Granado, O. Barreiro, E. Tejera, M. Yañez-Mó, V. R. Caiolfa, and F. Sanchez-Madrid, 2013; 33:3644-3658.

CD81 controls the organization of the immune synapse and T cell activation. Using synthetic peptides from LifeTein, Sanchez-Madrid lab demonstrated that CD81 is required for proper T cell activation. Many molecular techniques such as FRET assay, phosphorylation and other quantitative microscopy were used to prove the concept using synthetic peptides.

Journal of Molecular Biology, Effect of C-Terminal Sequence on Competitive Semaphorin Binding to Neuropilin-1, Matthew W. Parker, Andrew D. Linkugel, Craig W. Vander Kooi, 2013

Neuropilins (Nrp) ligands untilize a C-terminal domain for receptor engagement. This was confimed with the use of peptides synthesized by LifeTein. The binding assay showed that the C-1 position critically modulates Nrp binding and VEGF inhibitory potency. The data also reveal that a C-terminal proline-arginine motif allows optimal Nrp engagement by its ligands. Synthetic peptide is an important tool for the competitive binding studies and protein-protein interactions.

Biochemistry, Assembly of High Molecular Weight Complexes of Lipin on a Supported Lipid Bilayer Observed by Atomic Force Microscopy, Carl E. Creutz, James M. Eaton , and Thurl E. Harris, Article ASAP, DOI: 10.1021/bi4004765, Publication Date (Web): July 8, 2013

The flag peptide sequence MDFKDDDDK is widely used for fusion protein expression. The peptide MDFKDDDDK is recognized by anti-FLAG monoclonal antibodies. The binding reaction is also dependent on Calcium, so proteins can frequently be eluted from an affinity matrix by EDTA containing buffer. Using synthetic FLAG peptide from LifeTein, Carl E. Creutz from Harris lab studied the ability of lipin to form large complexes on membranes.

Plant Physiology Preview, Probing Arabidopsis chloroplast diacylglycerol pools by selectively targeting bacterial diacylglycerol kinase to suborganellar membranes. Bagyalakshmi Muthan, Rebecca L. Roston, John E. Froehlich, Christoph Benning, Published on July 9, 2013, as DOI:10.1104/pp.113.222513

Diacylglycerol (DAG) is a central metabolite in plant lipid metabolism. Studying an E.coli DAG kinase is a good approach to probe different DAG pools of chloroplast membranes in vivo. Using anti-DAGK or antiDAG kinase antisera from LifeTein, Bagyalakshmi Muthan from Benning's lab presented a full phenotypic analysis of stable transgenic Arabidopsis lines. And they further determined the accessibility of DAG pools generated on the outer leaflet of the chloroplast outer envelope membrane during osmotic stress.

Biochemistry, Processive degradation of unstructured protein by Escherichia coli Lon occurs via the slow, sequential delivery of multiple scissile sites followed by rapid and synchronized peptide bond cleavage events,2013, Natalie Mikita , Iteen Cheng , Jennifer Fishovitz , Jon Huang , and Irene Lee, DOI: 10.1021/bi4008319

Protein degradation is commonly found in ATP-dependent proteases. Natalie Mikita, using synthetic peptides from LifeTein, designed experiments to determine the timing of selected scissile sites to gain insights into the mechanism by which ATP-dependent proteases attain processivity in protein degradation. The results showed that the cleavage of multiple peptide bonds in an ATP-dependent manner. The delivery of all the scissile sites in λN to the proteolytic site is necessary.

Proteins: Structure, Function, and Bioinformatics, Delineation of key XRCC4/LigaseIV interfaces for targeted disruption of non-homologous end joining DNA repair, Meghan J. McFadden, Wilson K. Y. Lee, John D. Brennan, Murray S. Junop, 2013, DOI: 10.1002/prot.24349

Identifying proteins involved in DNA repair is becoming attractive method to study DNA repair pathways. Meghan J. McFadden, using synthetic peptides from LifeTein, found the minimal inhibitory fragment of the XRCC4-interacting region (XIR) capable of disrupting a complex of XRCC4/XIR. Helix 1 and loop regions of the helix-loop-helix clamp provide secondary target surfaces to identify adjuvant compounds that could be used in combination to more efficiently inhibit XRCC4/Ligase IV complex formation and DNA repair.

J. Biol. Chem., Batroxobin Binds Fibrin with Higher Affinity and Promotes Clot Expansion to a Greater Extent than Thrombin, Trang T. Vu, Alan R. Stafford, Beverly A. Leslie, Paul Y. Kim, James C. Fredenburgh, and Jeffrey I. Weitz, 2013; 288:16862-16871.

Batroxobin is a thrombin-like serine protease from the venom of Bothrops atrox moojeni that clots fibrinogen. Using synthetic peptide FpB from LifeTein, the Weitz lab found that batroxobin binds fibrin(ogen) with higher affinity than thrombin and promotes greater clot expansion. This interaction may contribute to its unique pattern of fibrinopeptide release.

J. Bacteriol., A Plasmid-Encoded Phosphatase Regulates Bacillus subtilis Biofilm Architecture, Sporulation, and Genetic Competence, JB.02030-12; published ahead of print 22 March 2013, doi: 10.1128/JB.02030-12

The formation of biofilms, contributes significantly to bacterial resistance to antibiotics and innate host defenses. Since biofilm resistance to antibiotics is mainly due to the slow growth rate and low metabolic activity of bacteria in such community, understanding the signaling pathways could be potentially an attractive therapeutic approach. Using synthetic peptides from LifeTein, Neiditch lab found that RapP regulates sporulation and genetic competence as a result of its ability to dephosphorylate Spo0F. RapP can be directly inhibited by peptide binding.

Sci Transl Med, Targeting the TLR Co-Receptor CD14 with TLR2-Derived Peptides Modulates Immune Responses to Pathogens, 15 May 2013: Vol. 5, Issue 185, p. 185ra64 (Sci. Transl. Med. DOI: 10.1126/scitranslmed.3005544)

Peptide screening and peptide binding assay were used to study the influence that CD14 exerts on TLR activities. The peptides were purchased from LifeTein. Peptides representing the targeted regions were used for immunization. It was found that the TLR-2 derived peptides modulated immune responses to pathogens. The study descrubed a potential therapeutic strategy to amplify responses to different pathogens mediated by different TLRs by targeting the common TLR co-receptor, CD14.

Therapeutic peptides, WO 2010023440 A1, Patent Application, Inventors: Mario Labeta, Nicholas Topley, Filing date: Aug 24, 2009

Therapeutic peptides derived from the extracellular region of human Toll-like receptor 2 (TLR2) are useful in the treatment of acute and chronic inflammatory conditions. Several human TLR2 peptides were purchased from LifeTein.

Cell Death and Disease (2013), IP3R2 levels dictate the apoptotic sensitivity of diffuse large B-cell lymphoma cells to an IP3R-derived peptide targeting the BH4 domain of Bcl-2, 4, e632; doi:10.1038/cddis.2013.140 Published online 16 May 2013.

Using cell penetrating peptides from LifeTein, The Bultynck lab targeted the BH4 domain of Bcl-2. The TAT peptide can carry the desired peptide sequence into cancer cell. The TAT peptide tools selectively targeting BH4-Bcl-2 are effective in DL-BCL cancer cells expressing high levels of IP3R2.

Journal of Virology, Cross-inhibition of ChikunGunya virus fusion and infection by alphavirus E1 domain III proteins, Claudia Sánchez San Martín, Soumya Nanda, Yan Zheng, Whitney Fields and Margaret Kielian, Published ahead of print 1 May 2013, doi: 10.1128/JVI.00814-13

Using anti-His monoclonal antibody (LT0426) from LifeTein, The Kielian lab detected His tagged CHIKV proteins. Their results supported the importance of the alphavirus E1 domain III stem region. The Alphavirus E1 homotrimer is important for the fusion protein refolding.

Ivy Yeuk Wah Chung and Mark Paetzel, Crystal Structures of Yellowtail Ascites Virus VP4 Protease, TRAPPING AN INTERNAL CLEAVAGE SITE TRANS ACYL-ENZYME COMPLEX IN A NATIVE SER/LYS DYAD ACTIVE SITE, THE JOURNAL OF BIOLOGICAL CHEMISTRY VOL. 288, NO. 18, pp. 13068 –13081, May 3, 2013

Fluorometric peptides by LifeTein were used as substrates for cleavage assays. The fluorometric peptide cleavage assay was performed with and without DTT. The polyprotein of VP4 contains an internal cleavage site. This renders the truncated VP4 protein proteolytically active. The serine-lysine dyad catalytic mechanism can be utilized for anti-virus drug design.

ET Smith, DA Johnson, Protein Science, 2013, Human enteropeptidase light chain: Bioengineering of recombinants and kinetic investigations of Structure and function, DOI: 10.1002/pro.2239

Synthetic peptides by LifeTein were used as substrate to study the protein structure and function. ET Smith and DA Johnson found that the positively charged peptides could contribute the substrate specificity in human enteropeptidase. It shows importance of the charge-charge interactions in the substrate binding pocket. For example, peptide DDDDK and DDDDR could have different specificities for substrates.

Paul M. Arnaboldi, et al. An outer surface protein C (OspC) peptide derived from Borrelia burgdorferi sensu strico as a target for the serodiagnosis of early Lyme disease, Published ahead of print 30 January 2013, Clinical and Vaccine Immunology, doi: 10.1128/CVI.00608-12

LifeTein advanced the research on serodiagnostic assays for Lyme disease. The linear epitopes OspC1 was synthesized by LifeTein. This highly conserved 20 amino acid peptide epitope detected specific IgM and/or IgG in 60 out of 98 serum samples. This OspC1 peptide could have value as a component of a multi-peptide Lyme disease serological assay with significantly improved capabilities for the diagnosis of early infection. OspC1 was proved to have higher specificity than the commercial available OspC peptide.

Justin A. Boddey, et al. Role of Plasmepsin V in Export of Diverse Protein Families from the Plasmodium falciparum Exportome, Traffic, Article first published online: 27 FEB 2013 DOI: 10.1111/tra.12053

PEXEL sequences were synthesized by LifeTein. It was found that the N terminal regions of the exported proteins can be cleaved by Plasmepsin V. Using the synthetic peptides, the authors probed the substrate specificity of Plasmepsin V and determined that lysine at the PECEL P3 position. Isoleucine at position P1 also blocked Plasmepsin V activity.

A Petrosyan, PW Cheng, Glycobiology, 2013, A non-enzymatic function of Golgi glycosyltransferases: Mediation of Golgi fragmentation by interaction with non-muscle myosin IIA, doi: 10.1093/glycob/cwt009

Synthetic peptides by LifeTein were used to study function of Golgi glycosyltransferases. It was found that the non-muscle myosin IIA (NMIIA) interacts with Golgi residential protein. The evidence showed the non-enzymatic function of Golgi glycosyltransferases.

JM Eaton, GR Mullins, DN Brindley, TE Harris, Journal of Biological Chemistry, 2013, Phosphorylation of lipin 1 and charge on the phosphatidic acid head group control its phosphatidic acid phosphatase activity and membrane association, doi:10.1074/jbc.M112.441493jbc.M112.441493.

The FLAG sequence DYKDDDDK is frequently used for affinity purification. Synthetic FLAG peptide by LifeTein was used in the elution buffer to purify lipin 1 protein. It was found that the Lipin 1 preferentially binds di-anionic phosphatidic acid and this is eliminated by phosphorylation.