Short hydrogen bonds in photoactive yellow protein
Short hydrogen bonds in photoactive yellow protein
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DOI：
10.1107/s090744490400616x
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发表时间：
2004-06-01
影响因子：
2.2
通讯作者：
Moffat, K
中科院分区：
文献类型：
--
作者：
Anderson, S;Crosson, S;Moffat, K
光活性黄蛋白（PYP）在各种条件下解决的基态的八个高分辨率晶体结构表明，它的发色团是由两个异常短的氢键稳定。Tyr 42 O-η和Glu 46 O-η与发色团酚氧的分离小于它们的原子货车范德华半径之和2.6埃。这是强氢键的特征，其中氢键获得显著的共价特征。从质子化的Glu 46到带负电荷的酚氧的氢键的长度为2.58 +/-0.01埃，而从Tyr 42到带负电荷的酚氧的氢键的长度显著更短，为2.49 +/-0.01埃。E46 Q突变体的解析度为0.95埃;电子等排突变使Glx 46与发色团的氢键长度增加了0.29 +/-0.01埃，达到平均氢键长度2.88 +/-0.01埃。Tyr 42的非常短的氢键解释了为什么突变这个残基对基态结构和PYP光循环有如此严重的影响。电子等排突变对光循环的影响在很大程度上可以通过改变这些氢键的长度和强度来解释。
Eight high-resolution crystal structures of the ground state of photoactive yellow protein (PYP) solved under a variety of conditions reveal that its chromophore is stabilized by two unusually short hydrogen bonds. Both Tyr42 O-eta and Glu46 O-epsilon are separated from the chromophore phenolate oxygen by less than the sum of their atomic van der Waals radii, 2.6 Angstrom. This is characteristic of strong hydrogen bonding, in which hydrogen bonds acquire significant covalent character. The hydrogen bond from the protonated Glu46 to the negatively charged phenolate oxygen is 2.58 +/- 0.01 Angstrom in length, while that from Tyr42 is considerably shorter, 2.49 +/- 0.01 Angstrom. The E46Q mutant was solved to 0.95 Angstrom resolution; the isosteric mutation increased the length of the hydrogen bond from Glx46 to the chromophore by 0.29 +/- 0.01 Angstrom to that of an average hydrogen bond, 2.88 +/- 0.01 Angstrom. The very short hydrogen bond from Tyr42 explains why mutating this residue has such a severe effect on the ground-state structure and PYP photocycle. The effect of isosteric mutations on the photocycle can be largely explained by the alterations to the length and strength of these hydrogen bonds.