Linking conformation change to hemoglobin activation via chain-selective time-resolved resonance Raman spectroscopy of protoheme/mesoheme hybrids.
Linking conformation change to hemoglobin activation via chain-selective time-resolved resonance Raman spectroscopy of protoheme/mesoheme hybrids.
复制标题
DOI：
10.1007/s00775-009-0487-7
复制
发表时间：
2009-06
影响因子：
3
通讯作者：
Spiro, Thomas G.
中科院分区：
文献类型：
--
作者：
Balakrishnan, Gurusamy;Ibrahim, Mohammed;Mak, Piotr J.;Hata, Jessica;Kincaid, James R.;Spiro, Thomas G.
报道了Hb四聚体的时间分辨共振拉曼光谱，其中α和β链被选择性地取代为中位血红素。Soret吸收带在中观相对于原血红素的移动允许链选择性激发血红素RR光谱。这些光谱在HbCO光解后的演变表明，这两条链的双键重组速率和产率是相同的，这与最近对15N-血红素同位素杂化的结果一致。光谱还显示了脱氧血红素ν4和νFe-His)RR带的系统位移，这是反相关的。这些位移是为蛋白质结构中的连续中间体解析的，这些中间体以前是从时间分辨的UVRR光谱中确定的。这两条链在即时光产物中都显示出Fe-His键的压缩，在第一个中间体Rdeoxy(0.07μS)的形成过程中该键松弛，其中近端的F-螺旋被提议远离血红素。随后，Fe-His键减弱，α比β链更弱。β链的减弱是逐渐的，但α链的减弱是突然的，与R-T四元转变的完成相吻合，在20μS，由于Hb在20μS也发生了从快重结合到慢重结合的转变，α链νFe-His的下降支持了Fe-His键从连接约束到张力的局部化，至少在α-链上是这样。在β链中，这种机制更为复杂。
Time-resolved Resonance Raman spectra are reported for Hb tetramers, in which the αand β chains are selectively substituted with mesoheme. The Soret absorbtion band shift in meso- relative to proto-heme permits chain-selective excitation of heme RR spectra. The evolution of these spectra following HbCO photolysis show that geminate recombination rates and yields are the same for the two chains, consistent with recent results on 15N-heme isotopomer hybrids. The spectra also reveal systematic shifts in the deoxy-heme ν4 and νFe-His) RR bands, which are anti-correlated. These shifts are resolved for the successive intermediates in the protein structure, which have previously been determined from time-resolved UVRR spectra. Both chains show Fe-His bond compression in the immediate photoproduct, which relaxes during the formation of the first intermediate, Rdeoxy (0.07 μs), in which the proximal F-helix is proposed to move away from the heme. Subsequently, the Fe-His bond weakens, more so for the α than the β chains. The weakening is gradual for the β chains, but abrupt for the α chains, coinciding with completion of the R-T quaternary transition, at 20μs. Since the transition from fast- to slow-rebinding Hb also occurs at 20μs, the drop in the α chain νFe-His supports the localization of ligation restraint to tension in the Fe-His bond, at least in the α-chains. The mechanism is more complex in the β chains.
登录
查看更多内容
影响因子：
48
作者：
Cammarata, Marco;Levantino, Matteo;Schotte, Friedrich;Anfinrud, Philip A.;Ewald, Friederike;Choi, Jungkweon;Cupane, Antonio;Wulff, Michael;Ihee, Hyotcherl
通讯作者：
Ihee, Hyotcherl
影响因子：
15
作者：
Guallar, V;Jarzecki, AA;Spiro, TG
通讯作者：
Spiro, TG
影响因子：
2.5
作者：
Juszczak, L;Samuni, U;Friedman, JM
通讯作者：
Friedman, JM
影响因子：
15
作者：
Hu, SZ;Smith, KM;Spiro, TG
通讯作者：
Spiro, TG
影响因子：
5.6
作者：
Balakrishnan, G;Tsai, CH;Spiro, TG
通讯作者：
Spiro, TG