Structure of a Novel Photoreceptor, the BLUF Domain of AppA from Rhodobacter sphaeroides
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- 作者：Spencer Anderson ; Vladimira Dragnea ; Shinji Masuda ; Joel Ybe ; Keith Moffat ; and Carl Bauer
- 刊名：Biochemistry
- 出版年：2005
- 出版时间：June 7, 2005
- 年：2005
- 卷：44
- 期：22
- 页码：7998 - 8005
- 全文大小：270K
- 年卷期：v.44,no.22(June 7, 2005)
- ISSN：1520-4995
文摘
The flavin-binding BLUF domain of AppA represents a new class of blue light photoreceptorsthat are present in a number of bacterial and algal species. The dark state X-ray structure of this domainwas determined at 2.3 Å resolution. The domain demonstrates a new function for the common ferredoxin-like fold; two long 
lpha.gif" BORDER=0>-helices flank the flavin, which is bound with its isoalloxazine ring perpendicular toa five-stranded 
le">-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 involvedin signaling. Nearly all residues conserved in BLUF domains surround the flavin chromophore, many ofwhich are involved in an intricate hydrogen bond network. Photoactivation may induce a rearrangementin this network via reorientation of the Gln63 side chain to form a new hydrogen bond to the flavin O4position. This shift would also break a hydrogen bond to the Trp104 side chain, which may be critical ininduction of global structural change in AppA.
lpha.gif" BORDER=0>-helices flank the flavin, which is bound with its isoalloxazine ring perpendicular toa five-stranded le">-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 involvedin signaling. Nearly all residues conserved in BLUF domains surround the flavin chromophore, many ofwhich are involved in an intricate hydrogen bond network. Photoactivation may induce a rearrangementin this network via reorientation of the Gln63 side chain to form a new hydrogen bond to the flavin O4position. This shift would also break a hydrogen bond to the Trp104 side chain, which may be critical ininduction of global structural change in AppA.