We apologize for Proteopedia being slow to respond. For the past two years, a new implementation of Proteopedia has been being built. Soon, it will replace this 18-year old system. All existing content will be moved to the new system at a date that will be announced here.
3mzi is a 6 chain structure with sequence from Synechocystis sp. pcc 6803. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
PixD (Slr1694) is a BLUF (blue-light-using FAD) photoreceptor used by the cyanobacterium Synechocystis sp. PCC6803 to control phototaxis toward blue light. In this study, we probe the involvement of a conserved Tyr8-Gln50-Met93 triad in promoting an output signal upon blue light excitation of the bound flavin. Analysis of acrylamide quenching of Trp91 fluorescence shows that the side chain of this residue remains partially solvent exposed in both the lit and dark states. Mutational analysis demonstrates that substitution mutations at Tyr8 and Gln50 result in the loss of the photocycle while a mutation of Met93 does not appreciably disturb the formation of the light-excited state and only minimally accelerates its decay from 5.7 to 4.5 s. However, mutations of Tyr8, Gln50, and Met93 disrupt the ability of PixD dimers to interact with PixE to form a higher-order PixD(10)-PixE(5) complex, which is indicative of a lit conformational state. Solution nuclear magnetic resonance spectroscopy and X-ray crystallographic analyses confirm that a Tyr8 to Phe mutation is locked in a pseudo-light-excited state revealing flexible areas in PixD that likely constitute part of an output signal upon light excitation of wild-type PixD.
Mutational and Structural Studies of the PixD BLUF Output Signal That Affects Light-Regulated Interactions with PixE.,Yuan H, Dragnea V, Wu Q, Gardner KH, Bauer CE Biochemistry. 2011 Jul 26;50(29):6365-75. Epub 2011 Jun 28. PMID:21688827[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
↑ Yuan H, Dragnea V, Wu Q, Gardner KH, Bauer CE. Mutational and Structural Studies of the PixD BLUF Output Signal That Affects Light-Regulated Interactions with PixE. Biochemistry. 2011 Jul 26;50(29):6365-75. Epub 2011 Jun 28. PMID:21688827 doi:10.1021/bi200701d
