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Physico-chemical and antigenic characterization of unconventional heavy chain antibodies of Indian desert camel (Camelus dromedarius L.)

Wed, 01 Dec 2004 00:00:00 GMT

Title: Physico-chemical and antigenic characterization of unconventional heavy chain antibodies of Indian desert camel (Camelus dromedarius L.) Authors: Sehrawat, Sharvan; Singh, Ajit Abstract: Heavy chain antibodies (HCAbs) of IgG2 and IgG3 subtypes were purified from the sera of Indian desert camel (Camelus dromedarius L.) by ammonium sulphate precipitation, followed by ion-exchange chromatography on DEAE-cellulose and affinity chromatography on protein A-sepharose and protein G-sepharose, and characterized by SOS-polyacrylamide gel electrophoresis, agar gel immunodiffusion (AGIO), counter-immunoelectrophoresis (CIEP), immunoelectrophoresis (IEP), ELISA and immunoblotting. IgG2 and IgG3 were found to have molecular mass 46.77 kDa and 43.65 kDa, respectively by SOS-PAGE under reducing conditions. They migrated in β-region in IEP and could be detected in CIEP, because of being more negatively charged and smaller size. Anti-camel IgG3 cross-reacted in AGIO, ELISA and immunoblotting with IgGs of pig and ruminants (cattle, buffalo, sheep and goat), but not with immunoglobulins from horse, dog, guinea pigs, mice, fish, poultry and human. The present findings suggest close antigenic relationship of camels with pigs and ruminants. Page(s): 299-304

Role of protein tyrosine kinase inhibitors in cancer therapeutics

Wed, 01 Dec 2004 00:00:00 GMT

Title: Role of protein tyrosine kinase inhibitors in cancer therapeutics Authors: Bhise, S B; Nalawade, Abhijit D; Wadhawa, Hitesh Abstract: Protein tyrosine kinases (PTKs) are critical in regulating cell growth and differentiation and are deeply involved in several cancers. PTK-inhibitors are mainly ATP-site directed and are finding use in the treatment of several cancers, and more than 30 such agents are now in phase I-III clinical trials. The present review focuses mainly on the development of PTK inhibitors in clinical trials, with special emphasis on imatinib mesylate, a rationally designed, potent oral anticancer agent and selective inhibitor for Abl tyrosine kinase, including Bcr-Abl, C-kit and platelet-derived growth factor-receptor tyrosine kinases, which has been implicated in several malignancies, including chronic myeloid leukemia and gastrointestinal stromal tumour. Page(s): 273-280

Comparative modelling of tetramanganese cluster of Chaetosphaeridium globosum

Fri, 01 Oct 2004 00:00:00 GMT

Title: Comparative modelling of tetramanganese cluster of Chaetosphaeridium globosum Authors: Rath, L S; Raval, M K Abstract: The D1 protein of photosystem II (PS II) complex of a micro-alga Chaetosphaeridium globosum has been theoretically modelled from its sequence using comparative modeling with known backbone structure of D1 protein from bacterium Thermosynechococcus vulcanus as template. The model is built with missing loops and all side chains, which are not resolved in the structure of the template. The structure of the tetramanganese cluster (TMC) and the ligand forming side chains have been subjected to modeling studies in order to gather more information useful to understanding of the water splitting reactions. Earlier models of TMC have been scrutinized and an insight into the manganese coordination sphere has been provided. Page(s): 258-262

Characterization of non-planar peptide groups in protein crystal structures

Fri, 01 Oct 2004 00:00:00 GMT

Title: Characterization of non-planar peptide groups in protein crystal structures Authors: Dasgupta, Anjan Kumar; Majumdar, Rabi; Bhattacharyya, Dhananjay Abstract: Peptide groups are generally assumed to be planar in protein structure, due to 'rigid' partial double bond character of peptide bonds, thus the value of peptide torsion angle ω should be restricted to 180° for the usual/rans form of peptide unit. However, on analyzing the ultra-high resolution protein crystal database, we find that in some cases, ω deviates> 10° from its usual value of 180°, indicating significant non-planarity of peptide groups. Moreover, the non-planarity for most of the amino acids is found to be 'biased' towards values of ω smaller than 180°. Similar trend for ω is confirmed by the neutron diffraction data for proteins. The neutron diffraction database also reveals that non-planar peptide groups are generally correlated to 'pyramidal' structure of the peptide-nitrogen bonds. Consequently, the hydrogen atom of peptide group deviates from its planar position, as measured by the 'improper' torsion angle θ. Thus, we find that both the angles ω and θ point towards a significant amount of non-planarity of peptide groups, which cannot be ignored. The role of peptide non-planarity in protein function is, however, not yet clear. Page(s): 233-240