1ZLG

Solution structure of the extracellular matrix protein anosmin-1

Summary for 1ZLG

• Entry DOI: 10.2210/pdb1zlg/pdb
• Related: 1fle 1fna 1igr
• Descriptor: Anosmin 1 (1 entity in total)
• Functional Keywords: insulin-like growth factor receptor cys-rich fold, whey acidic protein fold, fibronectin type iii fold, hormone-growth factor complex, hormone/growth factor
• Biological source: Homo sapiens (human)
• Cellular location: Cell membrane ; Peripheral membrane protein : P23352
• Total number of polymer chains: 1
• Total formula weight: 76545.12

Authors

Hu, Y.,Sun, Z.,Eaton, J.T.,Bouloux, P.M.,Perkins, S.J. (deposition date: 2005-05-06, release date: 2006-05-09, Last modification date: 2024-05-22)

Primary citation

Hu, Y.,Sun, Z.,Eaton, J.T.,Bouloux, P.M.,Perkins, S.J.
Extended and Flexible Domain Solution Structure of the Extracellular Matrix Protein Anosmin-1 by X-ray Scattering, Analytical Ultracentrifugation and Constrained Modelling.
J.Mol.Biol., 350:553-570, 2005

PubMed Abstract: Kallmann'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.

PubMed: 15949815
DOI: 10.1016/j.jmb.2005.04.031

Experimental method

SOLUTION SCATTERING