Structures of wild-type chloromet and L103N hydroxomet Themiste zostericola myohemerythrins at 1.8 angstrom resolution
Structures of wild-type chloromet and L103N hydroxomet Themiste zostericola myohemerythrins at 1.8 angstrom resolution
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DOI：
10.1021/bi9630422
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发表时间：
1997-06-10
期刊：
影响因子：
2.9
通讯作者：
Ellis, WR
中科院分区：
文献类型：
--
作者：
Martins, LJ;Hills, CP;Ellis, WR
肌红蛋白（Mhr）是一种非血红素铁氧载体，存在于海洋“花生”蠕虫的牵开肌中。报道了两个重组的Themiste zostericola Mhrs的X射线晶体结构，分辨率为1.8埃。令人惊讶的是，发现met野生型结构（R = 17.8%）含有与Fe 2结合的氯，而在met L103 N结构（R = 18.3%）中发现配位的氢氧化物。一个内部的水分子也被发现远端的Fe-O-Fe中心的突变蛋白，形成氢键与配位的氢氧化物和OD 1原子的Asn-103。这一发现与L103 N突变体Mhr的动力学和光谱结果一致[Raner，G. M.，马丁斯湖J.，& Ellis，W. R.，Jr.（1997）Biochemistry 36，7037-7043]。还讨论了残基103（野生型MHR中的Leu）在门控配体结合中的侧链的可能作用。
Myohemerythrin (Mhr) is a nonheme iron oxygen carrier found in the retractor muscles of marine ''peanut'' worms. The X-ray crystal structures of two recombinant Themiste zostericola Mhrs are reported to a resolution of 1.8 Angstrom. Surprisingly, the met wild-type structure (R = 17.8%) was found to contain chloride bound to Fe2, while coordinated hydroxide was found in the met L103N structure (R = 18.3%). An internal water molecule was also found distal to the Fe-O-Fe center of the mutant protein, forming hydrogen bonds with the coordinated hydroxide and the OD1 atom of Asn-103. This finding is consistent with the kinetic and spectroscopic results reported for the L103N mutant Mhr [Raner, G. M., Martins, L. J., & Ellis, W. R., Jr. (1997) Biochemistry 36, 7037-7043]. Possible roles for the side chain of residue 103 (Leu in wild-type Mhr) in gating ligand binding are also discussed.