Sticht H, Wildegger G, Bentrop D, Darimont B, Sterner R, Rösch P
Lehrstuhl für Biopolymere, Universität Bayreuth, Germany.
Eur J Biochem. 1996 May 1;237(3):726-35. doi: 10.1111/j.1432-1033.1996.0726p.x.
The solution structure of the 60-residue 1[Fe4-S4] ferredoxin from the hyperthermophilic bacterium Thermotoga maritima was determined based on 683 distance and 35 dihedral angle restraints that were obtained from NMR data. In addition, data known from crystallographic studies of ferredoxins was used for modeling of the iron-sulfur cluster and its environment. The protein shows a globular fold very similar to the fold of the related 1[Fe4-S4] ferredoxins from Desulfovibrio gigas and Desulfovibrio africanus, and elements of regular secondary structure similar to those in other ferredoxins were found in the T. maritima protein. In particular, the T. maritima protein displayed a beta-sheet structure made up of strands located at the very NH(2) and COOH termini of the protein, and an internal alpha-helix. The internal beta-sheet observed in the D. gigas and D. africanus ferredoxins could not be confirmed in T. maritima ferredoxin and is thus suggested to be only weakly present or even absent in this protein. This result suggests that thermostability in ferredoxins is not necessarily correlated with the content of stable elements of regular secondary structure.
基于从核磁共振数据获得的683个距离约束和35个二面角约束，确定了来自嗜热栖热菌的60个残基的1[Fe4-S4]铁氧化还原蛋白的溶液结构。此外，铁氧化还原蛋白晶体学研究已知的数据被用于铁硫簇及其环境的建模。该蛋白质呈现出一种球状折叠，与来自巨大脱硫弧菌和非洲脱硫弧菌的相关1[Fe4-S4]铁氧化还原蛋白的折叠非常相似，并且在嗜热栖热菌蛋白质中发现了与其他铁氧化还原蛋白中类似的规则二级结构元件。特别是，嗜热栖热菌蛋白质呈现出一种β-折叠结构，由位于蛋白质非常靠近NH(2)和COOH末端的链组成，以及一个内部α-螺旋。在巨大脱硫弧菌和非洲脱硫弧菌铁氧化还原蛋白中观察到的内部β-折叠在嗜热栖热菌铁氧化还原蛋白中未得到证实，因此表明在该蛋白质中仅微弱存在甚至不存在。该结果表明，铁氧化还原蛋白中的热稳定性不一定与规则二级结构的稳定元件含量相关。
