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From Proteopedia
Solution structure of the extracellular matrix protein anosmin-1
Structural highlights
DiseaseKALM_HUMAN Defects in KAL1 are the cause of hypogonadotropic hypogonadism 1 with or without anosmia (HH1) [MIM:308700. A disorder characterized by absent or incomplete sexual maturation by the age of 18 years, in conjunction with low levels of circulating gonadotropins and testosterone and no other abnormalities of the hypothalamic-pituitary axis. In some cases, it is associated with non-reproductive phenotypes, such as anosmia, cleft palate, and sensorineural hearing loss. Anosmia or hyposmia is related to the absence or hypoplasia of the olfactory bulbs and tracts. Hypogonadism is due to deficiency in gonadotropin-releasing hormone and probably results from a failure of embryonic migration of gonadotropin-releasing hormone-synthesizing neurons. In the presence of anosmia, idiopathic hypogonadotropic hypogonadism is referred to as Kallmann syndrome, whereas in the presence of a normal sense of smell, it has been termed normosmic idiopathic hypogonadotropic hypogonadism (nIHH).[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] FunctionKALM_HUMAN Has a dual branch-promoting and guidance activity, which may play an important role in the patterning of mitral and tufted cell collaterals to the olfactory cortex (By similarity). Chemoattractant for fetal olfactory epithelial cells.[14] 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 PubMedKallmann's syndrome corresponds to a loss of sense of smell and hypogonadotrophic hypogonadism. Defects in anosmin-1 result in the X-linked inherited form of Kallmann's syndrome. Anosmin-1 is an extracellular matrix protein comprised of an N-terminal, cysteine-rich (Cys-box) domain and a whey acidic protein-like (WAP) domain, followed by four fibronectin type III (FnIII) domains. The solution structures of recombinant proteins containing the first three domains (PIWF1) and all six domains (PIWF4) were determined by X-ray scattering and analytical ultracentrifugation. Guinier analyses showed that PIWF1 and PIWF4 have different radii of gyration (R(G)) values of 3.1 nm and 6.7 nm, respectively, but similar cross-sectional radii of gyration (R(XS)) values of 1.5 nm and 1.9 nm, respectively. Distance distribution functions showed that the maximum lengths of PIWF1 and PIWF4 were 11 nm and 23 nm, respectively. Analytical ultracentrifugation gave sedimentation coefficients of 2.52 S and 3.55 S for PIWF1 and PIWF4, respectively. The interpretation of the scattering data by constrained modelling requires homology models for all six domains in anosmin-1. While models were already available for the WAP and FnIII domains, searches suggested the Cys-box domain may resemble the cysteine-rich region of the insulin-like growth factor receptor. Automated constrained molecular modelling based on joining the anosmin-1 domains with structurally randomised linkers resulted in 10,000 models for anosmin-1. A trial-and-error search showed that about 0.1-1.4% of these models fitted the X-ray data. The best models showed that the three domains and six domains in PIWF1 and PIWF4, respectively, were extended. The inter-domain linkers in anosmin-1 could not all be extended at the same time, and there was evidence for inter-domain flexibility. Models with folded-back domain arrangements do not fit the data. These solution structures account for the known biological function of anosmin-1, in particular its ability to interact with its three macromolecular ligands. Extended and flexible domain solution structure of the extracellular matrix protein anosmin-1 by X-ray scattering, analytical ultracentrifugation and constrained modelling.,Hu Y, Sun Z, Eaton JT, Bouloux PM, Perkins SJ J Mol Biol. 2005 Jul 15;350(3):553-70. PMID:15949815[15] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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Categories: Homo sapiens | Large Structures | Bouloux PM | Eaton JT | Hu Y | Perkins SJ | Sun Z
