Davy S L, Breton J, Osborne M J, Thomson A J, Thurgood A P, Lian L Y, Pétillot Y, Hatchikian C, Moore G R
Centre for Metalloprotein Spectroscopy and Biology, School of Chemical Sciences, University of East Anglia, Norwich, UK.
Biochim Biophys Acta. 1994 Nov 16;1209(1):33-9. doi: 10.1016/0167-4838(94)90133-3.
Desulfovibrio africanus ferredoxin I was studied by magnetic circular dichroism and 1H-NMR spectroscopies. These showed the presence of histidine and tryptophan, in contrast to the previously reported amino-acid sequence (Bruschi and Hatchikian (1982) Biochimie 64, 503-507). This was redetermined and the revised sequence shown to contain both histidine and tryptophan, as well as four other corrections (Sery et al. (1994) Biochemistry, submitted). Electrospray mass spectrometry confirmed the mass of the ferredoxin was that given by the revised amino-acid sequence. The secondary structure of the ferredoxin I was investigated with two-dimensional 1H-NMR experiments and both alpha-helix and beta-sheet structure detected. The influence of the paramagnetism of the Fe4 S4 cluster on the NMR properties of the ferredoxin protons was investigated, by temperature-dependent experiments, and it was concluded that there is only a negligible dipolar contribution to resonance chemical shifts from this source. The significance of this for the determination of the three-dimensional structure of the ferredoxin by NMR is discussed.
利用磁圆二色光谱法和1H-NMR光谱法对非洲脱硫弧菌铁氧化还原蛋白I进行了研究。结果显示存在组氨酸和色氨酸，这与之前报道的氨基酸序列（Bruschi和Hatchikian（1982年），《生物化学》64卷，503 - 507页）不同。重新测定了该序列，修订后的序列显示既含有组氨酸和色氨酸，还有其他四处修正（Sery等人（1994年），《生物化学》，待发表）。电喷雾质谱法证实了铁氧化还原蛋白的质量与修订后的氨基酸序列相符。通过二维1H-NMR实验研究了铁氧化还原蛋白I的二级结构，检测到了α-螺旋和β-折叠结构。通过温度依赖性实验研究了Fe4 S4簇的顺磁性对铁氧化还原蛋白质子NMR性质的影响，得出结论：由此产生的对共振化学位移的偶极贡献可忽略不计。讨论了这一点对于通过NMR确定铁氧化还原蛋白三维结构的意义。
