Fodor S P, Bogomolni R A, Mathies R A
Department of Chemistry, University of California, Berkeley 94720.
Biochemistry. 1987 Oct 20;26(21):6775-8. doi: 10.1021/bi00395a029.
Time-resolved resonance Raman spectra of the hRL intermediate of halorhodopsin have been obtained. The structurally sensitive fingerprint region of the hRL spectrum is very similar to that of bacteriorhodopsin's L550 intermediate, which is known to have a 13-cis configuration. This indicates that hRL contains a 13-cis chromophore and that an all-trans----13-cis isomerization occurs in the halorhodopsin photocycle. hRL exhibits a Schiff base stretching mode at 1644 cm-1, which shifts to 1620 cm-1 in D2O. This demonstrates that the Schiff base linkage to the protein is protonated. The insensitivity of the C-C stretching mode frequencies to N-deuteriation suggests that the Schiff base configuration is anti. The 24 cm-1 shift of the Schiff base mode in D2O indicates that the Schiff base proton in hRL has a stronger hydrogen-bonding interaction with the protein than does hR578.
已获得嗜盐菌视紫红质hRL中间体的时间分辨共振拉曼光谱。hRL光谱中结构敏感的指纹区域与细菌视紫红质的L550中间体非常相似，已知L550中间体具有13-顺式构型。这表明hRL含有13-顺式发色团，并且在嗜盐菌视紫红质光循环中发生了全反式----13-顺式异构化。hRL在1644 cm-1处表现出席夫碱伸缩模式，在D2O中该模式移至1620 cm-1。这表明与蛋白质的席夫碱连接是质子化的。C-C伸缩模式频率对N-氘化不敏感，表明席夫碱构型为反式。席夫碱模式在D2O中的24 cm-1位移表明，hRL中的席夫碱质子与蛋白质的氢键相互作用比hR578更强。
