Figure 2

A structure-based alignment of V. carchairae chitinase A with S. marcescens chitinase A and B. circulans chitinase A1. A) The N-terminal ChBDs of V. carchariae chitinase A (residues 22–138) and S. marcescens chitinase A (residues 24–137) were aligned with the C-terminal fragment (residues 648–699), covering the ChBD of B. circulans WL-12 chitinase A1. B) An alignment of the catalytic domain of the three bacterial chitinases with residues 160 to 289 of V. carchariae chitinase A being displayed. The chitinase sequences were retrieved from the Swiss-Prot/TreEMBL protein databases, aligned using "MegAlign" in the DNASTAR package, and displayed in Genedoc. The secondary structure of V. carchariae chitinase A was predicted from the PHD method in PredictProtein using S. marcescens as template [see texts]. Conserved residues are shaded in blue, whereas the residues that are aligned with Ser33, Trp70, Trp231, and Tyr245 of V. carchariae chitinase A are shaded in red. ChiA_Vibca: V. carchariae chitinase A (Q9AMP1), ChiA_Serma: S. marcescens chitinase A (P07254), and ChiA1_Bacc: B. circulans chitinase A1 (P20533). β-strand is represented by an arrow, α-helix by a cylinder and loop by a straight line.