Structure of a novel photoreceptor, the BLUF domain of AppA from Rhodobacter sphaeroides
Structure of a novel photoreceptor, the BLUF domain of AppA from Rhodobacter sphaeroides
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DOI：
10.1021/bi0502691
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发表时间：
2005-06-07
期刊：
影响因子：
2.9
通讯作者：
Bauer, C
中科院分区：
文献类型：
--
作者：
Anderson, S;Dragnea, V;Bauer, C
AppA 的黄素结合 BLUF 结构域代表了一类新的蓝光光感受器，存在于许多细菌和藻类物种中。该域的暗态 X 射线结构以 2.3 埃分辨率确定。该结构域展示了常见铁氧还蛋白样折叠的新功能；黄素侧面有两个长的α螺旋，黄素与垂直于五链β-折叠的iscialloxazine环结合。 BLUF 结构域的氢键网络和整体蛋白质拓扑（但不是其序列）与 LOV 结构域（广泛参与信号传导的 PAS 结构域的子集）有一些相似之处。 BLUF 结构域中几乎所有保守的残基都围绕黄素发色团，其中许多残基参与复杂的氢键网络。光活化可能通过 Gln63 侧链的重新定向来诱导该网络中的重排，从而在黄素 04 位置上形成新的氢键。这种转变还会破坏 Trp104 侧链的氢键，这对于诱导 AppA 的整体结构变化可能至关重要。
The flavin-binding, BLUF domain of AppA represents a new class of blue light photoreceptors that are present in a number of bacterial and algal species. The dark state X-ray structure of this domain was determined at 2.3 angstrom resolution. The domain demonstrates a new function for the common ferredoxin-like fold; two long a-helices flank the flavin, which is bound with its iscialloxazine ring perpendicular to a five-stranded beta-sheet. The hydrogen bond network and the overall protein topology of the BLUF domain (but not its sequence) bear some resemblance to LOV domains, a subset of PAS domains widely involved in signaling. Nearly all residues conserved in BLUF domains surround the flavin chromophore, many of which are involved in an intricate hydrogen bond network. Photoactivation may induce a rearrangement in this network via reorientation of the Gln63 side chain to form a new hydrogen bond to the flavin 04 position. This shift would also break a hydrogen bond to the Trp104 side chain, which may be critical in induction of global structural change in AppA.