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137 a.a.
_CA
Key reference
DOI no: 10.1021/bi701317g Biochemistry 46:11352-11360 (2007) PubMed id: 17850114
Carbohydrate Recognition by a Large Sialidase Toxin from Clostridium perfringens. A.B.Boraston, E.Ficko-Blean, M.Healey. ABSTRACT
Myonecrotic isolates of Clostridium perfringens secrete multimodular sialidases, often termed "large sialidases", that contribute to the virulence of this bacterium. NanJ is the largest of the two secreted sialidases at 1173 amino acids and comprises 6 different modules which are, from the N-terminus, a family 32 carbohydrate binding module (CBM), a family 40 CBM, a family 33 glycoside hydrolase, a module of unknown function, a family 82 "X-module" of unknown function, and a module with amino acid similarity to fibronectin type III domains. The hydrolase activity of clostridial sialidases is quite well documented; however, the functions of their accessory domains are entirely uninvestigated. Here we describe the carbohydrate binding activity of the isolated family 32 CBM (CBM32) and the isolated family 40 CBM (CBM40). CBM32 is shown to bind galactose or N-acetylgalactosamine, while CBM40 is sialic acid specific, though both CBMs appear to bind with very low affinities. The crystal structure of CBM32 was determined at 2.25 A in complex with galactose. This revealed what appears to be a very simple galactose binding site. The crystal structure of CBM40 was determined at 2.20 A in complex with a sialic acid containing molecule that it fortuitously crystallized with, revealing the molecular details of the CBM40-sialic acid interaction. Overall, the results indicate that NanJ contains carbohydrate specific binding modules that likely function to target the enzyme to molecules or cells bearing mixed populations of glycans that terminate in either galactose/N-acetylgalactosamine or sialic acid.
Literature references that cite this PDB file's key reference
PubMed id Reference
19193644 E.Ficko-Blean, K.J.Gregg, J.J.Adams, J.H.Hehemann, M.Czjzek, S.P.Smith, and A.B.Boraston (2009).
Portrait of an enzyme, a complete structural analysis of a multimodular {beta}-N-acetylglucosaminidase from Clostridium perfringens.J Biol Chem, 284, 9876-9884.
PDB codes: 2v5c 2v5d 2w1n
19124471 H.Connaris, P.R.Crocker, and G.L.Taylor (2009).
Enhancing the Receptor Affinity of the Sialic Acid-binding Domain of Vibrio cholerae Sialidase through Multivalency.J Biol Chem, 284, 7339-7351.
PDB code: 2w68
18716000 J.J.Adams, K.Gregg, E.A.Bayer, A.B.Boraston, and S.P.Smith (2008).
Structural basis of Clostridium perfringens toxin complex formation.Proc Natl Acad Sci U S A, 105, 12194-12199.
PDB codes: 2ozn 2vo8
18292090 K.J.Gregg, R.Finn, D.W.Abbott, and A.B.Boraston (2008).
Divergent modes of glycan recognition by a new family of carbohydrate-binding modules.J Biol Chem, 283, 12604-12613.
PDB codes: 2vmg 2vmh 2vmi 2vng 2vno 2vnr The most recent references are shown first. Citation data come partly from CiteXplore and partly from an automated harvesting procedure. Note that this is likely to be only a partial list as not all journals are covered by either method. However, we are continually building up the citation data so more and more references will be included with time. Where a reference describes a PDB structure, the PDB codes are shown on the right.
