Engineering Photocycle Dynamics

Daan M. F. van Aalten, Andrea Haker, Johnny Hendriks, Klaas J. Hellingwerf, Leemor Joshua-Tor, Wim Crielaard
2001 Journal of Biological Chemistry  
Crystallographic and spectroscopic analyses of three hinge-bending mutants of the photoactive yellow protein are described. Previous studies have identified Gly 47 and Gly 51 as possible hinge points in the structure of the protein, allowing backbone segments around the chromophore to undergo large concerted motions. We have designed, crystallized, and solved the structures of three mutants: G47S, G51S, and G47S/G51S. The protein dynamics of these mutants are significantly affected. Transitions
more » ... fected. Transitions in the photocycle, measured with laser induced transient absorption spectroscopy, show rates up to 6-fold different from the wild type protein and show an additive effect in the double mutant. Compared with the native structure, no significant conformational differences were observed in the structures of the mutant proteins. We conclude that the structural and dynamic integrity of the region around these mutations is of crucial importance to the photocycle and suggest that the hinge-bending properties of Gly 51 may also play a role in PAS domain proteins where it is one of the few conserved residues.
doi:10.1074/jbc.m109313200 pmid:11714713 fatcat:laxumcue6nbevn6koc27fop63u