2iw0
From Proteopedia
Structure of the chitin deacetylase from the fungal pathogen Colletotrichum lindemuthianum
Structural highlights
FunctionCDA_COLLN Hydrolyzes the N-acetamido groups of N-acetyl-D-glucosamine polymers in chitin to form chitosan and acetate (PubMed:15555935, PubMed:16232493, PubMed:16878976, PubMed:7592838, PubMed:8987657, PubMed:9373940). May play a role in evasion of the host immune response; plant chitinases liberate chitin molecules from the fungal cell wall which act as elicitors of the plant immune response, deacetylation of the liberated chitin neutralizes elicitor activity (PubMed:10913295, PubMed:8987657).[1] [2] [3] [4] [5] [6] [7] [8] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe fungal pathogen Colletotrichum lindemuthianum secretes an endo-chitin de-N-acetylase (ClCDA) to modify exposed hyphal chitin during penetration and infection of plants. Although a significant amount of biochemical data is available on fungal chitin de-N-acetylases, no structural data exist. Here we describe the 1.8 A crystal structure of a ClCDA product complex and the analysis of the reaction mechanism using Hammett linear free energy relationships, subsite probing, and atomic absorption spectroscopy studies. The structural data in combination with biochemical data reveal that ClCDA consists of a single domain encompassing a mononuclear metalloenzyme which employs a conserved His-His-Asp zinc-binding triad closely associated with the conserved catalytic base (aspartic acid) and acid (histidine) to carry out acid/base catalysis. The data presented here indicate that ClCDA possesses a highly conserved substrate-binding groove, with subtle alterations that influence substrate specificity and subsite affinity. Strikingly, the structure also shows that the hexahistidine purification tag appears to form a tight interaction with the active site groove. The enzyme requires occupancy of at least the 0 and +1 subsites by (GlcNAc)(2) for activity and proceeds through a tetrahedral oxyanion intermediate. Structure and mechanism of chitin deacetylase from the fungal pathogen Colletotrichum lindemuthianum.,Blair DE, Hekmat O, Schuttelkopf AW, Shrestha B, Tokuyasu K, Withers SG, van Aalten DM Biochemistry. 2006 Aug 8;45(31):9416-26. PMID:16878976[9] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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