Marked differences between metalloproteases meprin A and B in substrate and peptide bond specificity
Marked differences between metalloproteases meprin A and B in substrate and peptide bond specificity
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DOI：
10.1074/jbc.m011414200
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发表时间：
2001-04-20
影响因子：
4.8
通讯作者：
Bond, JS
中科院分区：
文献类型：
--
作者：
Bertenshaw, GP;Turk, BE;Bond, JS
Meprin A和B是高度调节的、分泌的和细胞表面的金属内肽酶，在肾脏和肠道中大量表达。Meprin寡聚体由进化上相关的α和/或β亚基组成。本文的工作是为了鉴定对小鼠蜂胶水解酶敏感的生物活性多肽和蛋白质，并对其进行动力学表征。胃肠道调节分子胃泌素释放肽片段14-27和胃泌素17分别是梅普林A和B的最佳底物。多肽文库和各种自然产生的多肽表明，meprin p亚基对底物的P1和P1‘位具有明显的酸性氨基酸偏好。在P1和P1‘位的小残基(如丝氨酸、丙氨酸)或疏水性残基(如苯丙氨酸)选择的是meprinα亚基，而在P2’位，Pro是最受欢迎的氨基酸。因此，尽管meprinα和β亚基在蛋白酶域中有55%的氨基酸同源性，并且通常定位于相同的组织细胞表面，但它们具有非常不同的底物和肽键特性，表明不同的功能。基于ASTASIN晶体结构的小鼠meprinα和β蛋白酶域的同源模型揭示了活性位置的差异，这可以解释这两个亚基在底物专一性上的显著差异。
Meprin A and B are highly regulated, secreted, and cell-surface metalloendopeptidases that are abundantly expressed in the kidney and intestine. Meprin oligomers consist of evolutionarily related alpha and/or beta subunits. The work herein was carried out to identify bioactive peptides and proteins that are susceptible to hydrolysis by mouse meprins and kinetically characterize the hydrolysis. Gastrin-releasing peptide fragment 14-27 and gastrin 17, regulatory molecules of the gastrointestinal tract, were found to be the best peptide substrates for meprin A and B, respectively. Peptide libraries and a variety of naturally occurring peptides revealed that the meprin p subunit has a clear preference for acidic amino acids in the P1 and P1 ' sites of substrates. The meprin alpha subunit selected for small (e,g, serine, alanine) or hydrophobic (e.g, phenylalanine) residues in the P1 and P1 ' sites, and proline was the most preferred amino acid at the P2 ' position. Thus, although the meprin alpha and beta subunits share 55% amino acid identity within the protease domain and are normally localized at the same tissue cell surfaces, they have very different substrate and peptide bond specificities indicating different functions. Homology models of the mouse meprin alpha and beta protease domains, based on the astacin crystal structure, revealed active site differences that can account for the marked differences in substrate specificity of the two subunits.