1a67
CHICKEN EGG WHITE CYSTATIN WILDTYPE, NMR, 16 STRUCTURES
Structural highlights
FunctionCYT_CHICK This protein binds tightly to and inhibits a variety of thiol proteases including ficin, papain, and cathepsins B, C, H, and L. Although isolated from egg white, it is also present in serum. 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 solution structures of the phosphorylated form of native chicken cystatin and the recombinant variant AEF-S1M-M29I-M89L were determined by 2D, 3D and 4D-NMR. The structures turn out to be very similar, despite the substitutions and the phosphorylation of the wild-type. Their dominant feature is a five-stranded beta-sheet, which is wrapped around a five-turn alpha-helix, as shown by X-ray crystallographic studies of wild-type chicken cystatin. However, the NMR analysis shows that the second helix observed in the crystal is not present in solution. The phosphorylation occurs at S80, which is located in a flexible region. For this reason, very few effects on the structure are observed. Comparison of structures of the unphosphorylated variant and the wild-type shows small effects on H84 which is located in the supposed recognition site of the serine kinase. This recognition site appears to be well structured as a large loop-containing bulge of the beta-sheet. The N termini of both mutants, which contribute to a large extent to the binding to the proteinase, are very flexible. A loop structure involving the residues L7 to A10 as found in related inhibitors, such as in the kininogen domains 2 and 3, is not sufficiently populated to be observed. The structures of native phosphorylated chicken cystatin and of a recombinant unphosphorylated variant in solution.,Dieckmann T, Mitschang L, Hofmann M, Kos J, Turk V, Auerswald EA, Jaenicke R, Oschkinat H J Mol Biol. 1993 Dec 20;234(4):1048-59. PMID:8263912[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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