The hemopexin family is a family of evolutionarily related proteins. Hemopexin-like repeats occur in vitronectin and some matrix metalloproteinases family (matrixins).[1] The HX repeats of some matrixins bind tissue inhibitor of metallopeptidases (TIMPs).
Hemopexin (EC 3.2.1.35) is a serum glycoprotein that binds haem and transports it to the liver for breakdown and iron recovery, after which the free hemopexin returns to the circulation.[2] Hemopexin prevents haem-mediated oxidative stress. Structurally hemopexin consists of two similar halves of approximately two hundred amino acid residues connected by a histidine-rich hinge region. Each half is itself formed by the repetition of a basic unit of some 35 to 45 residues. Hemopexin-like domains have been found in two other types of proteins, vitronectin,[3] a cell adhesion and spreading factor found in plasma and tissues, and matrixins MMP-1, MMP-2, MMP-3, MMP-9, MMP-10, MMP-11, MMP-12, MMP-14, MMP-15 and MMP-16, members of the matrix metalloproteinase family that cleave extracellular matrix constituents.[4] These zinc endopeptidases, which belong to MEROPS peptidase subfamily M10A, have a single hemopexin-like domain in their C-terminal section. It is suggested that the hemopexin domain facilitates binding to a variety of molecules and proteins, for example the HX repeats of some matrixins bind tissue inhibitor of metallopeptidases (TIMPs).
Examples
Human gene encoding proteins containing hemopexin-like repeats include:
- HPX (hemopexin, the founding member of this protein family)
- matrix metalloproteinases: MMP1, MMP2, MMP3, MMP8, MMP9, MMP10, MMP11, MMP12, MMP13, MMP14, MMP15, MMP16, MMP17, MMP19, MMP20, MMP21, MMP24, MMP25, MMP27, MMP28,
- PRG4 (proteoglycan 4), and
- VTN (vitronectin).
References
- ^ Bode W (June 1995). "A helping hand for collagenases: the haemopexin-like domain". Structure. 3 (6): 527–30. doi:10.1016/s0969-2126(01)00185-x. PMID 8590012.
- ^ Altruda F, Tolosano E (2002). "Hemopexin: structure, function, and regulation". DNA Cell Biol. 21 (4): 297–306. doi:10.1089/104454902753759717. PMID 12042069.
- ^ Kojima K, Ogawa H, Matsumoto I, Yoneda A (1998). "Characterization of the ligand binding activities of vitronectin: interaction of vitronectin with lipids and identification of the binding domains for various ligands using recombinant domains". Biochemistry. 37 (18): 6351–6360. doi:10.1021/bi972247n. PMID 9572850.
- ^ Das S, Mandal M, Chakraborti T, Mandal A, Chakraborti S (2003). "Structure and evolutionary aspects of matrix metalloproteinases: a brief overview". Mol. Cell. Biochem. 253 (1–2): 31–40. doi:10.1023/A:1026093016148. PMID 14619953.
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This page was last edited on 6 July 2021, at 21:06