The Primary Structure of [beta].sup.I-Chain of Hemoglobin from Snake Sindhi Krait

The amino acid sequence of [beta].sup.I-globin chain from Sindhi Krait (Bungarus sindanus sindanus) was determined to study the molecular evolution among snakes. The hemoglobin was isolated from the red blood cells and was analyzed by ion-exchange chromatography (IEX). The crude globin was subjected to reversed phased-high performance liquid chromatography (RP-HPLC) using C4 column. The N-terminal sequences of intact globin chains and tryptic peptides were determined by Edman degradation in a pulsed liquid gas phase sequencer using an online Phenylthiohydantoin analyzer. Sindhi Krait is expected to express three hemoglobin components that are composed of [beta].sup.II, [beta].sup.I, [alpha].sup.D and [alpha].sup.A-globin chains, as apparent by IEX, RP-HPLC and N-terminal sequence analyses. Sequence alignment and phylogenetic analyses of [beta].sup.I globin chain from Sindhi Krait showed closest relationship with [beta].sup.I globin chain from Rattlesnake, Water snake and Indigo snake. Interestingly, comparison of primary sequence of [beta].sup.I globin chain of Sindhi Krait with human [beta] chain revealed 63 % similarity along with the retention of all heme contact points. Variations among the two sequences were prominent at [alpha][beta] contact points and in regions directly not important for function.