Manufacturing of insulin and its analogues relied upon in vitro enzymatic cleavages of its precursor forms (single chain precursor, SCP) at both ends of a connecting peptide (C-peptide) that links the respective B-chain and A-chains to corresponding final forms. We have demonstrated a simplified approach of cleaving P. pastoris expressed SCP, distinctly at one site for conversion to insulin glargine.
View Article and Find Full Text PDFWe present here extensive mass spectrometric studies on the formation of a Tris conjugate with a therapeutic monoclonal antibody. The results not only demonstrate the reactive nature of the Tris molecule but also the sequence and reaction conditions that trigger this reactivity. The results corroborate the fact that proteins are, in general, prone to conjugation and/or adduct formation reactions and any modification due to this essentially leads to formation of impurities in a protein sample.
View Article and Find Full Text PDFInsulin glargine is a slow acting analog of insulin used in diabetes therapy. It is produced by recombinant DNA technology in different hosts namely E. coli and Pichia pastoris.
View Article and Find Full Text PDFGlargine is an analog of Insulin currently being produced by recombinant DNA technology using two different hosts namely Escherichia coli and Pichia pastoris. Production from E. coli involves the steps of extraction of inclusion bodies by cell lysis, refolding, proteolytic cleavage and purification.
View Article and Find Full Text PDFThe benefits of statins, commonly prescribed for hypercholesterolemia, in treating Alzheimer's disease (AD) have not yet been fully established. A recent randomized clinical trial did not show any therapeutic effects of two statins on cognitive function in AD. Interestingly, however, the results of the Rotterdam study, one of the largest prospective cohort studies, showed reduced risk of AD in statin users.
View Article and Find Full Text PDFProtein mannosyltransferases (PMTs) catalyze the O-mannosylation of serine and threonine residues of proteins in the endoplasmic reticulum. The five PMT genes coding for protein mannosyltransferases, designated as PMT1, 2, 4, 5 and 6, were identified from Pichia pastoris genome based on the homology to PMT genes in Saccharomyces cerevisiae genome, which has seven PMT genes. The homologues of S.
View Article and Find Full Text PDFFormation of cyclic intermediates involving water or ammonia loss is a common occurrence in any reaction involving terminal amines or hydroxyl group containing species. Proteins that have both these functional groups in abundance are no exception, and presence of amino acids such as asparagine, glutamines, aspartic acids, and glutamic acids aid in formation of such intermediates. In the biopharma scenario, such intermediates lead to product- or process-related impurities that might be immunogenic.
View Article and Find Full Text PDFIrbesartan, a partial agonist of peroxisome proliferators activated receptor-γ (PPARγ), has been reported to improve insulin resistance and lipid profile in patients with diabetes mellitus or metabolic syndrome (MS). However, the down effectors of PPARγ have yet to be elucidated. Thus, in this study, we focused on the role of the hepatocyte growth factor (HGF) in the anti-metabolic effects of irbesartan, using apolipoprotein E (ApoE) knockout (KO) mice.
View Article and Find Full Text PDFBackground: Lipoprotein (a) (Lp(a)) is one of the risk factors for peripheral artery disease (PAD). Our previous report demonstrated that hepatocyte growth factor (HGF) gene therapy attenuated the impairment of collateral formation in Lp(a) transgenic mice. Since risk factors for atherosclerosis accelerate endothelial senescence and impair angiogenesis, we examined the role of Lp(a) in dysfunction and senescence of endothelial progenitor cells (EPC) and endothelial cells.
View Article and Find Full Text PDFBio-catalytic in vitro multistep reactions can be combined in a single step in one pot by optimizing multistep reactions under identical reaction condition. Using this analogy, the process of making PEGylated insulin, IN-105, was simplified. Instead of taking the purified active insulin bulk powder as the starting material for the conjugation step, an insulin process intermediate, partially purified insulin ester, was taken as starting material.
View Article and Find Full Text PDFSerotonin (5-hydroxytryptamine, 5-HT) plays a crucial role in peripheral artery disease (PAD) and diabetes mellitus (DM). In these conditions, the balance between the 5-HT2A receptor in smooth muscle cells and the 5-HT1B receptor in endothelial cells (ECs) regulates vascular tonus. In the present study, we focused on the role of 5-HT in endothelial dysfunction using a selective 5-HT2A receptor blocker, sarpogrelate.
View Article and Find Full Text PDFNonstructural protein 3 of the severe acute respiratory syndrome (SARS) coronavirus includes a "SARS-unique domain" (SUD) consisting of three globular domains separated by short linker peptide segments. This work reports NMR structure determinations of the C-terminal domain (SUD-C) and a two-domain construct (SUD-MC) containing the middle domain (SUD-M) and the C-terminal domain, and NMR data on the conformational states of the N-terminal domain (SUD-N) and the SUD-NM two-domain construct. Both SUD-N and SUD-NM are monomeric and globular in solution; in SUD-NM, there is high mobility in the two-residue interdomain linking sequence, with no preferred relative orientation of the two domains.
View Article and Find Full Text PDFThe nuclear magnetic resonance (NMR) structure of a globular domain of residues 1071 to 1178 within the previously annotated nucleic acid-binding region (NAB) of severe acute respiratory syndrome coronavirus nonstructural protein 3 (nsp3) has been determined, and N- and C-terminally adjoining polypeptide segments of 37 and 25 residues, respectively, have been shown to form flexibly extended linkers to the preceding globular domain and to the following, as yet uncharacterized domain. This extension of the structural coverage of nsp3 was obtained from NMR studies with an nsp3 construct comprising residues 1066 to 1181 [nsp3(1066-1181)] and the constructs nsp3(1066-1203) and nsp3(1035-1181). A search of the protein structure database indicates that the globular domain of the NAB represents a new fold, with a parallel four-strand beta-sheet holding two alpha-helices of three and four turns that are oriented antiparallel to the beta-strands.
View Article and Find Full Text PDFSequence-specific NMR assignments of the globular core comprising the residues 1066-1181 within the non-structural protein nsp3e from the SARS coronavirus have been obtained using triple-resonance NMR experiments with the uniformly [(13)C, (15)N]-labeled protein. The backbone and side chain assignments are nearly complete, providing the basis for the ongoing NMR structure determination. A preliminary identification of regular secondary structures has been derived from the (13)C chemical shifts.
View Article and Find Full Text PDFThe nuclear magnetic resonance (NMR) structure of a central segment of the previously annotated severe acute respiratory syndrome (SARS)-unique domain (SUD-M, for "middle of the SARS-unique domain") in SARS coronavirus (SARS-CoV) nonstructural protein 3 (nsp3) has been determined. SUD-M(513-651) exhibits a macrodomain fold containing the nsp3 residues 528 to 648, and there is a flexibly extended N-terminal tail with the residues 513 to 527 and a C-terminal flexible tail of residues 649 to 651. As a follow-up to this initial result, we also solved the structure of a construct representing only the globular domain of residues 527 to 651 [SUD-M(527-651)].
View Article and Find Full Text PDFSevere acute respiratory syndrome (SARS) coronavirus infection and growth are dependent on initiating signaling and enzyme actions upon viral entry into the host cell. Proteins packaged during virus assembly may subsequently form the first line of attack and host manipulation upon infection. A complete characterization of virion components is therefore important to understanding the dynamics of early stages of infection.
View Article and Find Full Text PDFCharacterization of the low energy excited states on the energy landscape of a protein is one of the exciting and challenging problems in structural biology today. In this context, we present here residue level NMR description of the low energy excited states representing locally different alternative conformations in the dynein light chain protein, in its dimeric as well as monomeric forms. Important differences have been observed between the two cases and these are not necessarily restricted to the dimer interface.
View Article and Find Full Text PDFSequence-specific NMR assignments of an internal domain of the protein nsp3, nsp3(513-651), which is a part of the SARS coronavirus (SARS-CoV) replicase polyprotein, have been determined, using triple-resonance NMR experiments with the uniformly [(13)C,(15)N]-labeled protein. The complete assignments (>99%) provide the basis for the ongoing three-dimensional structure determination.
View Article and Find Full Text PDFWe present circular dichroism (CD), steady state fluorescence and multidimensional NMR investigations on the equilibrium unfolding of monomeric dynein light chain protein (DLC8) by urea and guanidine hydrochloride (GdnHCl). Quantitative analysis of the CD and fluorescence denaturation curves reveals that urea unfolding is a two-state process, whereas guanidine unfolding is more complex. NMR investigations in the native state and in the near native states created by low denaturant concentrations enabled residue level characterization of the early structural and dynamic perturbations by the two denaturants.
View Article and Find Full Text PDFBiophysical studies in proteases are severely hampered due to the auto-cleavage property of these enzymes. In this context, we develop here a kinetic model and an NMR-based strategy to use this very autolytic property to derive useful insights into multiple unfolding pathways and mutational plasticities in these proteins. The basic idea lies in the interpretation of the auto-cleavage-driven decay of the folded protein peaks in the HSQC spectra as a function of time.
View Article and Find Full Text PDFRapid resonance assignment is a key requirement in structural genomics research by NMR. In this context we present here two new pulse sequences, namely, HNN-A and HN(C)N-A that have been developed by simple modification of the previously described pulse sequences, HNN and HN(C)N [S.C.
View Article and Find Full Text PDFDynamin, a protein playing crucial roles in endocytosis, oligomerizes to form spirals around the necks of incipient vesicles and helps their scission from membranes. This oligomerization is known to be mediated by the GTPase effector domain (GED). Here we have characterized the structural features of recombinant GED using a variety of biophysical methods.
View Article and Find Full Text PDFDynein light chain protein, a part of the cytoplasmic motor assembly, is a homodimer at physiological pH and dissociates below pH 4.5 to a monomer. The dimer binds to a variety of cargo, whereas the monomer does not bind any of the target proteins.
View Article and Find Full Text PDFAutoprocessing of HIV-1 protease (PR) precursors is a crucial step in the generation of the mature protease. Very little is known regarding the molecular mechanism and regulation of this important process in the viral life cycle. In this context we report here the first and complete residue level investigations on the structural and folding characteristics of the 17-kDa precursor TFR-PR-C(nn) (161 residues) of HIV-1 protease.
View Article and Find Full Text PDFWe recently described a triple resonance experiment, HN(C)N, for sequential correlation of H(N) and 15N atoms in (15N, 13C) labeled proteins [J. Biomol. NMR.
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