2i99 | pdb_00002i99
Crystal structure of human Mu_crystallin at 2.6 Angstrom
Structural highlights
Function[CRYM_HUMAN] Specifically catalyzes the reduction of imine bonds in brain substrates that may include cystathionine ketimine (CysK) and lanthionine ketimine (LK). Binds thyroid hormone which is a strong reversible inhibitor. Presumably involved in the regulation of the free intracellular concentration of triiodothyronine and access to its nuclear receptors.[1] 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 PubMedHuman cytosolic 3,5,3'-triiodo-L-thyronine-binding protein, also called mu-crystallin or CRYM, plays important physiological roles in transporting 3,5,3'-triiodo-L-thyronine (T(3)) into nuclei and regulating thyroid-hormone-related gene expression. The crystal structure of human CRYM's bacterial homolog Pseudomonas putida ornithine cyclodeaminase and Archaeoglobus fulgidus alanine dehydrogenase have been available, but no CRYM structure has been reported. Here, we report the crystal structure of human CRYM bound with NADPH refined to 2.6 A, and there is one dimer in the asymmetric unit. The structure contains two domains: a Rossmann fold-like NADPH-binding domain and a dimerization domain. Different conformations of the loop Arg83-His92 have been observed in two monomers of human CRYM in the same asymmetric unit. The peptide bond of Val89-Pro90 is a trans-configuration in one monomer but a cis-configuration in the other. A detailed comparison of the human mu-crystallin structure with its structurally characterized homologs including the overall comparison and superposition of active sites was conducted. Finally, a putative T(3)-binding site in human CRYM is proposed based on comparison with structural homologs. Crystal structure of human micro-crystallin complexed with NADPH.,Cheng Z, Sun L, He J, Gong W Protein Sci. 2007 Feb;16(2):329-35. PMID:17242435[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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