title: Structure of the photoactive yellow protein reconstituted with caffeic acid at 1.16 A resolution.
abstract: A structural study is described of the photoactive yellow protein (PYP) reconstituted with the chromophore derivative 3,4-dihydroxycinnamic acid. The crystal structure of PYP reconstituted with this chromophore at 1.16 A resolution is reported in space group P6(5). This is the first high-resolution structure of a photoreceptor containing a modified chromophore. The introduction of an extra hydroxyl group in the native chromophore (i.e. p-coumaric acid) appears to perturb the structure of the hybrid yellow protein only slightly. The chromophore is bound by the protein in two different conformations, separated by a rotation of 180 degrees of the catechol ring. In combination with available spectroscopic data, it is concluded that the caffeic acid chromophore binds to the protein in a strained conformation, which leads to a faster ejection from the chromophore-binding pocket upon pB formation.
authors.affiliation: W. M. Keck Structural Biology, Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA.
authors.forename: Daan M F
authors.initials: DM
authors.lastname: van Aalten
authors.forename: Wim
authors.initials: W
authors.lastname: Crielaard
authors.forename: Klaas J
authors.initials: KJ
authors.lastname: Hellingwerf
authors.forename: Leemor
authors.initials: L
authors.lastname: Joshua-Tor
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry*; D002109:Caffeic Acids / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D020283:Photoreceptors, Microbial
chemical_list: D001426:Bacterial Proteins; D002109:Caffeic Acids; D020283:Photoreceptors, Microbial; C050162:photoactive yellow protein, Bacteria; C040048:caffeic acid