Envelope diversity, characteristics of V3 region and predicted co-receptor usage of human immunodeficiency viruses infecting north indians

Subtypes of human immunodeficiency virus type 1 circulating in 21 north Indian patients were characterized based on the partial sequence of the gp120 envelope protein. A majority of viruses (85.7%, 18/21) were subtype C, while 14.3% (3/21) were subtype A. Sequence analysis revealed that the V3 region was highly conserved compared with V4 and V5. The predicted use of co-receptors indicated exclusive usage of R5, except for two subtype A viruses (AIIMS279 and AIIMS281). Our results demonstrate conservation within the V3 loop of subtype C viruses, and suggest the emergence of non-clade C viruses in the north Indian population.     

Electron factors in peroxidase properties and the mechanism of activation of oxygen with heme-containing proteins

A quantum-chemical calculation was carried out for the electronic structure of coordination compounds of general formula FeP (L1) (L2) (P-porphine; L1-imidazole or imidazolate; L2-CO, O2 or is absent), modelling the active sites of number of hemoproteins. The elucidation of electronic structures of the complexes under consideration explains the similar shapes and band positions of optical absorption and magnetic circular dichroism spectra of oxy- and carboxycomplexes of myoglobin, hemoglobin, and peroxidase. It is shown that the Coulomb repulsion between electrons of the lone pair of the imidazolate distal nitrogen leads to the transfer of the electronic density from this ligand to the dioxygen. This results in the strong dioxygen activation leading, in particular, to the high catalytical activity of peroxidase.