Ulrich E L, Krogmann D W, Markley J L
J Biol Chem. 1982 Aug 25;257(16):9356-64.
Cytochrome c553 is a photosynthetic electron transport protein found in algae and cyanobacteria. We have purified cytochromes c553 from five cyanobacteria and studied the structures of the ferrocytochromes by 1H NMR spectroscopy at 360 and 470 MHz. Using standard NMR techniques and by comparing the amino acid sequences of four cytochromes c553 with their 1H NMR spectra, we have assigned in the spectrum of the Aphanizomenon flos-aquae protein 18 resonances to specific amino acid residues and 12 resonances to specific heme protons. Steady state and truncated driven nuclear Overhauser enhancement experiments indicate that a tyrosine and methionine are located near pyrrole ring IV of the heme and that a phenylalanine ring is near the heme alpha-mesoproton. The general folding of the cytochrome c553 protein backbone appears to resemble that of Pseudomonas aeruginosa cytochrome c551, but the chirality of the cytochrome c553 axial methine sulfur is R, the same as that of horse heart cytochrome c.
细胞色素c553是一种存在于藻类和蓝细菌中的光合电子传递蛋白。我们从五种蓝细菌中纯化了细胞色素c553，并通过在360和470 MHz下的1H NMR光谱研究了亚铁细胞色素的结构。使用标准NMR技术，并通过比较四种细胞色素c553的氨基酸序列与其1H NMR光谱，我们在水华束丝藻蛋白的光谱中为特定氨基酸残基指定了18个共振峰，为特定血红素质子指定了12个共振峰。稳态和截断驱动核Overhauser增强实验表明，一个酪氨酸和一个甲硫氨酸位于血红素的吡咯环IV附近，并且一个苯丙氨酸环靠近血红素α-中质子。细胞色素c553蛋白质主链的一般折叠似乎类似于铜绿假单胞菌细胞色素c551，但细胞色素c553轴向次甲基硫的手性为R，与马心细胞色素c相同。
