Primary Citation of Related Structures: 6HPV, 6HT9
PubMed Abstract:
Mammalian fetuin-A and fetuin-B are abundant serum proteins with pleiotropic functions. Fetuin-B is a highly selective and potent inhibitor of metallo-peptidases (MPs) of the astacin family, which includes ovastacin in mammals. By inhibiting ovastacin, fetuin-B is essential for female fertility ...
Mammalian fetuin-A and fetuin-B are abundant serum proteins with pleiotropic functions. Fetuin-B is a highly selective and potent inhibitor of metallo-peptidases (MPs) of the astacin family, which includes ovastacin in mammals. By inhibiting ovastacin, fetuin-B is essential for female fertility. The crystal structure of fetuin-B was determined unbound and in complex with archetypal astacin, and it was found that the inhibitor has tandem cystatin-type modules (CY1 and CY2). They are connected by an exposed linker with a rigid, disulfide-linked 'CPDCP-trunk', and are followed by a C-terminal region (CTR) with little regular secondary structure. The CPDCP-trunk and a hairpin of CY2 form a bipartite wedge, which slots into the active-site cleft of the MP. These elements occupy the nonprimed and primed sides of the cleft, respectively, but spare the specificity pocket so that the inhibitor is not cleaved. The aspartate in the trunk blocks the catalytic zinc of astacin, while the CY2 hairpin binds through a QWV X GP motif. The CY1 module assists in structural integrity and the CTR is not involved in inhibition, as verified by in vitro studies using a cohort of mutants and variants. Overall, the inhibition conforms to a novel 'raised-elephant-trunk' mechanism for MPs, which is reminiscent of single-domain cystatins that target cysteine peptidases. Over 200 sequences from vertebrates have been annotated as fetuin-B, underpinning its ubiquity and physiological relevance; accordingly, sequences with conserved CPDCP- and QWV X GP-derived motifs have been found from mammals to cartilaginous fishes. Thus, the raised-elephant-trunk mechanism is likely to be generally valid for the inhibition of astacins by orthologs of fetuin-B.
Related Citations:
Fetuin-B, a second member of the fetuin family in mammals. Olivier, E., Soury, E., Ruminy, P., Husson, A., Parmentier, F., Daveau, M., Salier, J.P. (2000) Biochem J 350 Pt 2: 589
Tissue distribution and activity testing suggest a similar but not identical function of fetuin-B and fetuin-A. Denecke, B., Graber, S., Schafer, C., Heiss, A., Woltje, M., Jahnen-Dechent, W. (2003) Biochem J 376: 135
Fetuin-B, a liver-derived plasma protein is essential for fertilization. Dietzel, E., Wessling, J., Floehr, J., Schafer, C., Ensslen, S., Denecke, B., Rosing, B., Neulen, J., Veitinger, T., Spehr, M., Tropartz, T., Tolba, R., Renne, T., Egert, A., Schorle, H., Gottenbusch, Y., Hildebrand, A., Yiallouros, I., Stocker, W., Weiskirchen, R., Jahnen-Dechent, W. (2013) Dev Cell 25: 106
Mammalian gamete fusion depends on the inhibition of ovastacin by fetuin-B. Stocker, W., Karmilin, K., Hildebrand, A., Westphal, H., Yiallouros, I., Weiskirchen, R., Dietzel, E., Floehr, J., Jahnen-Dechent, W. (2014) Biol Chem 395: 1195
Fetuin B Is a Secreted Hepatocyte Factor Linking Steatosis to Impaired Glucose Metabolism. Meex, R.C., Hoy, A.J., Morris, A., Brown, R.D., Lo, J.C., Burke, M., Goode, R.J., Kingwell, B.A., Kraakman, M.J., Febbraio, M.A., Greve, J.W., Rensen, S.S., Molloy, M.P., Lancaster, G.I., Bruce, C.R., Watt, M.J. (2015) Cell Metab 22: 1078
Association of high fetuin-B concentrations in serum with fertilization rate in IVF: a cross-sectional pilot study. Floehr, J., Dietzel, E., Neulen, J., Rosing, B., Weissenborn, U., Jahnen-Dechent, W. (2016) Hum Reprod 31: 630
Recombinant fetuin-B protein maintains high fertilization rate in cumulus cell-free mouse oocytes. Dietzel, E., Floehr, J., Van de Leur, E., Weiskirchen, R., Jahnen-Dechent, W. (2017) Mol Hum Reprod 23: 25
The novel adipokine/hepatokine fetuin B in severe human and murine diabetic kidney disease. Kralisch, S., Hoffmann, A., Kloting, N., Bachmann, A., Kratzsch, J., Bluher, M., Zhang, M.Z., Harris, R.C., Stumvoll, M., Fasshauer, M., Ebert, T. (2017) Diabetes Metab 43: 465
Maternal malnourishment induced upregulation of fetuin-B blunts nephrogenesis in the low birth weight neonate. Rabadi, M.M., Abdulmahdi, W., Nesi, L., Jules, E., Marghani, Y., Sheinin, E., Tilzer, J., Gupta, S., Chen, S., Cassimatis, N.D., Lipphardt, M., Kozlowski, P.B., Ratliff, B.B. (2018) Dev Biol 443: 78
Mammalian plasma fetuin-B is a selective inhibitor of ovastacin and meprin metalloproteinases. Karmilin, K., Schmitz, C., Kuske, M., Korschgen, H., Olf, M., Meyer, K., Hildebrand, A., Felten, M., Fridrich, S., Yiallouros, I., Becker-Pauly, C., Weiskirchen, R., Jahnen-Dechent, W., Floehr, J., Stocker, W. (2019) Sci Rep 9: 546
Organizational Affiliation:
Proteolysis Laboratory, Department of Structural Biology, Molecular Biology Institute of Barcelona, CSIC, Barcelona Science Park, Helix Building, c/o Baldiri Reixac 15-21, E-08028 Barcelona, Catalonia, Spain.
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