Crystal structure of human cystatin D, a cysteine peptidase inhibitor with restricted inhibition profile.

• Cystatins 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 to 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 Arg26-cystatin D and solved its structures at room temperature and at cryo conditions to 2.5 and 1.8 Å resolution, respectively. Human cystatin D presents the typical cystatin fold, with a five-stranded anti-parallel -sheet wrapped around a five-turn -helix. The structures reveal differences in the peptidase-interacting regions when compared to other cystatins, providing plausible explanations to the restricted inhibitory specificity of cystatin D for some papain-like peptidases, and its lack of reactivity towards legumain-related enzymes. This is the final, accepted and revised manuscript of this article. Use alternative location to go to the published article. Requires subscription.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Farmakologi och toxikologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Pharmacology and Toxicology (hsv//eng)

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Läkemedelskemi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Medicinal Chemistry (hsv//eng)

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