野生型氯高铁血红素和L103N羟基高铁血红素米氏辐肛参肌红蛋白在1.8埃分辨率下的结构。
Structures of wild-type chloromet and L103N hydroxomet Themiste zostericola myohemerythrins at 1.8 A resolution.
作者信息
Martins L J, Hill C P, Ellis W R
机构信息
Department of Chemistry, University of Utah, Salt Lake City 84112, USA.
出版信息
Biochemistry. 1997 Jun 10;36(23):7044-9. doi: 10.1021/bi9630422.
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 A. 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.
肌红血球素（Mhr）是一种在海洋“花生”蠕虫的伸缩肌中发现的非血红素铁氧载体。据报道，两种重组的多毛纲沙蠋肌红血球素的X射线晶体结构分辨率达到了1.8埃。令人惊讶的是，在高铁野生型结构（R = 17.8%）中发现有氯离子与Fe2结合，而在高铁L103N结构（R = 18.3%）中发现有配位氢氧根。在突变蛋白的Fe-O-Fe中心远端还发现了一个内部水分子，它与配位氢氧根和Asn-103的OD1原子形成氢键。这一发现与L103N突变型Mhr的动力学和光谱学结果一致[拉纳，G.M.，马丁斯，L.J.，& 埃利斯，W.R.，Jr.（1997年）《生物化学》36卷，7037 - 7043页]。还讨论了103位残基（野生型Mhr中的亮氨酸）侧链在控制配体结合方面可能发挥的作用。
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