NMR comparison of prokaryotic and eukaryotic cytochromes c.
NMR comparison of prokaryotic and eukaryotic cytochromes c.
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原核和真核细胞色素的 NMR 比较 c．
DOI：
10.1021/bi00473a012
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发表时间：
1990
期刊：
影响因子：
2.9
通讯作者：
Timkovich,R
中科院分区：
文献类型：
--
作者：
Chau,MH;Cai,ML;Timkovich,R
美国阿拉巴马大学化学系，美国阿拉巴马州塔斯卡卢萨35687-0336摘要：用H NMR对铜绿假单胞菌（Pseudomonas aeruginosa, ATCC 19429）的铁细胞色素c-551在pH值为3.5 ~ 10.6、温度为4 ~ 60℃的条件下进行了研究，提出了主链和侧链质子的共振分配。细胞色素c-551与马细胞色素c （Wand et al.(1989)，生物化学28,186-194）和酵母iso-1细胞色素突变体（Pielak et al.(1988)）的结果比较。J. Biochem. 177, 167-177)揭示了所有细胞色素中不寻常的化学变化的一些独特的共振，这些化学变化可能作为血红素区域的标记。细胞色素c-551的结果表明，在较小的原核细胞色素中，所有苯甲酸侧链在核磁共振时间尺度上快速翻转。相反，在真核细胞色素中，有一些环在核磁共振时间尺度上缓慢翻转。铁细胞色素c-551经历了一个与pH有关的转变，pK约为7。指定共振的pH值行为提供了质子化位点是内部或埋藏的17-丙酸血红素取代基（IUPAC-IUB卟啉命名法）的证据。在内血红素丙酸取代基附近的片段上观察到构象不均匀性。
Department of Chemistry, University of Alabama, Tuscaloosa, Alabama 35687-0336 Received October 27, 1989; Revised Manuscript Received January 30, 1990 abstract:* H NMR spectroscopy has been used toexamine ferrocytochrome c-551 from Pseudomonas aeruginosa (ATCC 19429) over the pH range 3.5-10.6 and the temperature range 4-60 C. Resonance assignments are proposed for main-chain and side-chain protons. Comparison of results for cytochrome c-551 torecently assigned spectra for horse cytochrome c (Wand et al.(1989) Biochemistry 28, 186-194) and mutants of yeast iso-1 cytochrome (Pielak et al.(1988) Eur. J. Biochem. 177, 167-177) reveals some unique resonances with unusual chemical shifts in all cytochromes that may serve as markers for the heme region. Results for cytochrome c-551 indicate that in the smaller prokaryotic cytochrome, all benzoid side chains are rapidly flipping on the NMR time scale. In contrast, in eukaryotic cytochromes there are some rings flipping slowly on the NMR time scale. The ferrocytochrome c-551 undergoes a transition linked to pH with a pK around 7. The pH behavior of assigned resonances provides evidence that the site of protonation is the inner or buried 17-propionic acid heme substituent (IUPAC-IUB porphyrin nomenclature). Conformational heterogeneity has been observed for segments near the inner heme propionate substituent.