{PDOC50940} {PS50940; CHIT_BIND_II} {BEGIN} **************************************** * Chitin-binding type-2 domain profile * **************************************** The species distribution of the chitin-binding type-2 domain is complementary to the chitin-binding type-1 domain (see ). The type-2 is mainly found in animal and baculovirus proteins while the type-1 is found in plant and fungi. Type-2 is characterized by having a 6-cysteine motif: C-x(13,20)-C-x(5,6)-C-x(9,19)-C-x(10,14)-C-x(4,14)-C and several aromatic residues [1]. The structure of the chitin-binding domain of tachycitin has been solved (see ) [2]. It revealed that tachycitin shares a remarkable structural similarity with the chitin-binding type-1 domain of hevein. The overall structure forms a distorted beta-sandwich constructed by three-stranded and two-stranded beta-sheets connected through a bending loop (Cys-40-Leu-44). The precise chitin binding site (Cys-40 to Gly-60) is perfectly superposable with the chitin binding site of hevein. Furthermore a disulfide bridge connecting Cys-40 and Cys-53 is also present at the same location in the hevein structure [2]. Some protein known to contain a chitin-binding type-2 domain are listed below: - Animal class-II chitinase. It degrades chitin and chitotriose. In mammals it may participate in the defense against nematodes and other pathogens [3]. - Tachycitin, an antimicrobial protein of horseshoe crab hemocytes. - Peritrophin-A, a component of peritrophic matrices (acellular linings in the gut of most insects that comprise proteins and sugar polymers, including chitin). - Drosophila Tequila protein, a serine protease involved in immune response. - Drosophila Hemolectin, a sugar binding protein involved in defense response. The profile we developed covers the whole domain. -Sequences known to belong to this class detected by the profile: ALL. -Other sequence(s) detected in Swiss-Prot: NONE. -Last update: July 2016 / Profile revised. [ 1] Gaines P.J., Walmsley S.J., Wisnewski N. "Cloning and characterization of five cDNAs encoding peritrophin-A domains from the cat flea, Ctenocephalides felis." Insect Biochem. Mol. Biol. 33:1061-1073(2003). PubMed=14563358 [ 2] Suetake T., Tsuda S., Kawabata S., Miura K., Iwanaga S., Hikichi K., Nitta K., Kawano K. "Chitin-binding proteins in invertebrates and plants comprise a common chitin-binding structural motif." J. Biol. Chem. 275:17929-17932(2000). PubMed=10770921; DOI=10.1074/jbc.C000184200; [ 3] Tjoelker L.W., Gosting L., Frey S., Hunter C.L., Trong H.L., Steiner B., Brammer H., Gray P.W. "Structural and functional definition of the human chitinase chitin-binding domain." J. Biol. Chem. 275:514-520(2000). PubMed=10617646 -------------------------------------------------------------------------------- PROSITE is copyrighted by the SIB Swiss Institute of Bioinformatics and distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives (CC BY-NC-ND 4.0) License, see https://prosite.expasy.org/prosite_license.html -------------------------------------------------------------------------------- {END}