1rn7 | pdb_00001rn7
Structure of human cystatin D
Structural highlights
Function[CYTD_HUMAN] Cysteine proteinase inhibitor that possibly plays a protective role against proteinases present in the oral cavity. The order of preference for inhibition is cathepsin S > cathepsin H > cathepsin L > cathepsin B.[1] 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 PubMedCystatins are natural inhibitors of papain-like (family C1) and legumain-related (family C13) cysteine peptidases. Cystatin D is a type 2 cystatin, a secreted inhibitor found in human saliva and tear fluid. Compared with its homologues, cystatin D presents an unusual inhibition profile with a preferential inhibition cathepsin S > cathepsin H > cathepsin L and no inhibition of cathepsin B or pig legumain. To elucidate the structural reasons for this specificity, we have crystallized recombinant human Arg(26)-cystatin D and solved its structures at room temperature and at cryo conditions to 2.5- and 1.8-A resolution, respectively. Human cystatin D presents the typical cystatin fold, with a five-stranded anti-parallel beta-sheet wrapped around a five-turn alpha-helix. The structures reveal differences in the peptidase-interacting regions when compared with other cystatins, providing plausible explanations for the restricted inhibitory specificity of cystatin D for some papain-like peptidases and its lack of reactivity toward legumain-related enzymes. Crystal structure of human cystatin D, a cysteine peptidase inhibitor with restricted inhibition profile.,Alvarez-Fernandez M, Liang YH, Abrahamson M, Su XD J Biol Chem. 2005 May 6;280(18):18221-8. Epub 2005 Feb 23. PMID:15728581[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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