Fold-recognition and comparative modeling of human alpha2,3-sialyltransferases reveal their sequence and structural similarities to CstII from Campylobacter jejuni.
Abstract
The 3-D structure of none of the eukaryotic sialyltransferases (SiaTs) has been determined so far. Sequence alignment algorithms such as BLAST and PSI-BLAST could not detect a homolog of these enzymes from the protein databank. SiaTs, thus, belong to the hard/medium target category in the CASP experiments. The objective of the current work is to model the 3-D structures of human SiaTs which transfer the sialic acid in alpha2,3-linkage viz., ST3Gal I, II, III, IV, V, and VI, using fold-recognition and comparative modeling methods. The pair-wise sequence similarity among these six enzymes ranges from 41 to 63%. Unlike the sequence similarity servers, fold-recognition servers identified CstII, a alpha2,3/8 dual-activity SiaT from Campylobacter jejuni as the homolog of all the six ST3Gals; the level of sequence similarity between CstII and ST3Gals is only 15-20% and the similarity is restricted to well-characterized motif regions of ST3Gals. Deriving template-target sequence alignments for the entire ST3Gal sequence was not straightforward: the fold-recognition servers could not find a template for the region preceding the L-motif and that between the L- and S-motifs. Multiple structural templates were identified to model these reg...Continue Reading
References
Molecular cloning and expression of human Gal beta 1,3GalNAc alpha 2,3-sialytransferase (hST3Gal II)
Citations
Software Mentioned
Related Concepts
Related Feeds
Campylobacteriosis (ASM)
Campylobacteriosis is caused by the bacteria Campylobacter jejuni and is a common cause of gastroenteritis in humans. Discover the latest research on Campylobacteriosis here.
Cajal Bodies & Gems
Cajal bodies or coiled bodies are dense foci of coilin protein. Gemini of Cajal bodies, or gems, are microscopically similar to Cajal bodies. It is believed that Cajal bodies play important roles in RNA processing while gems assist the Cajal bodies. Find the latest research on Cajal bodies and gems here.