Journal
ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY
Volume 68, Issue -, Pages 1207-1216Publisher
INT UNION CRYSTALLOGRAPHY
DOI: 10.1107/S090744491202495X
Keywords
-
Funding
- Ministry of Education, Science, Sports and Culture of Japan
- Japan Society for the Target Protein Project
- Program of Basic Research Activities for Innovative Biosciences (PROBRAIN) of Japan
- Grants-in-Aid for Scientific Research [23580112, 23380049, 11J40009] Funding Source: KAKEN
Ask authors/readers for more resources
The structures of two mutants (H192A and Y246F) of a mannuronate-specific alginate lyase, A1-III, from Sphingomonas species A1 complexed with a tetrasaccharide substrate [4-deoxy-l-erythro-hex-4-ene-pyranosyluronate-(mannuronate)(2)-mannuronic acid] were determined by X-ray crystallography at around 2.2 angstrom resolution together with the apo form of the H192A mutant. The final models of the complex forms, which comprised two monomers (of 353 amino-acid residues each), 268-287 water molecules and two tetrasaccharide substrates, had R factors of around 0.17. A large conformational change occurred in the position of the lid loop (residues 64-85) in holo H192A and Y246F compared with that in apo H192A. The lid loop migrated about 14 angstrom from an open form to a closed form to interact with the bound tetrasaccharide and a catalytic residue. The tetrasaccharide was bound in the active cleft at subsites -3 to +1 as a substrate form in which the glycosidic linkage to be cleaved existed between subsites -1 and +1. In particular, the O-eta atom of Tyr68 in the closed lid loop forms a hydrogen bond to the side chain of a presumed catalytic residue, O-eta of Tyr246, which acts both as an acid and a base catalyst in a syn mechanism.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available