Isolation, reconstitution and functional characterisation of the Rhodobacter sphaeroides photoactive yellow protein.
We report the isolation, functional reconstitution and photophysical characterisation of Rhodobacter sphaeroides photoactive yellow protein (PYP), of which the gene was recently cloned. Reconstitution of the his-tagged purified apo-protein with 4-hydroxy-cinnamic acid yields the characteristic blue absorbance at 446 nm, but surprisingly also an absorbance peak at 360 nm. This additional peak is not caused by binding of a second chromophore, as confirmed with mass spectroscopy. Moreover, reconstitution with the 'locked' analogue 7-hydroxy-coumarin-3-carboxylic acid yields only a single absorbance peak at 441 nm. The 446 nm and 360 nm species are part of a temperature- and pH-dependent equilibrium. Photoactivation of the protein leads to formation of a blue-shifted intermediate as in other PYPs, with a 100-fold increased groundstate recovery rate (k(pB-->pG)=500 s(-1)) compared to E-PYP.
Haker
A
A
Laboratory for Microbiology, E.C. Slater Institute, BioCentrum, University of Amsterdam, Nieuwe Achtergracht 127, 1018 WS, Amsterdam, The Netherlands.
Hendriks
J
J
Gensch
T
T
Hellingwerf
K
K
Crielaard
W
W
D001059:Apoproteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D003373:Coumaric Acids / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D013058:Mass Spectrometry; D020283:Photoreceptors, Microbial; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D012242:Rhodobacter sphaeroides / Q000737:chemistry* / Q000235:genetics; D013057:Spectrum Analysis; D013696:Temperature
D001059:Apoproteins; D001426:Bacterial Proteins; D003373:Coumaric Acids; D020283:Photoreceptors, Microbial; D011993:Recombinant Fusion Proteins; C050162:photoactive yellow protein, Bacteria