results.
bioinformatic analysis of the ''cellulose synthase-like''(cslAsc) gene in S.coelicolor.
The S.coelicolor genome contains only one gene (SCO2836) encoding a cellulose synthase-like protein has weak similarity to the catalytic subunits ofcellulose synthases from bacteria and plants. We there fore named SCO2836 cslAsc (cellulose synthase-like gene of S.coelicolor) . Orthologs of cslAsc were also found in streptomyces avermitilis MA-4680(19) and Streptomyces nanchangensis (35). Structure prediction suggested that the protein has seven transmembrane domains. with the N terminus being cytoplasmid and the C terminus outsids the membrane. the large cytoplasmid domain in the middle region contains domains that match entries pfam03552 (cellulose synthase)(E value,2e-9), from aa 338 to 451,and PF00535(glycosycosyltransferasefamily)(E value, le-7),from aa 166 to 342(26). The central active site of cellulose synthases is thought to comprise four particulaarly conserved subregions (U1 through U4) that contain the conserved Asp(D) residues(in U1 to U3 )and the motif QXXRW (in U4)(32).These are considered essential for substrate binding and catalysis (32),and they are present in CslA(Fig. 1A). The residue of a normally conserved KAG motif is replaced by H and aQTP motif is not conserved in CslAsc, but the function of these two motifs in cellulose synthase are not yet establihed.