Journal article

Phytochrome three-dimensional structures and functions


Authors listHughes, J

Publication year2010

Pages710-716

JournalBiochemical Society Transactions

Volume number38

Issue number2

ISSN0300-5127

DOI Linkhttps://doi.org/10.1042/BST0380710

PublisherPortland Press


Abstract
The complete three-dimensional sensory module structures of the Pr ground state of Synechocystis 6803 (phi and the unusual Pfr ground state of the bacteriophytochrome PaBphP (PDB codes 2VEA and 3C2W respectively) have now been solved, revealing an asymmetrical dumbbell form made up of a PAS (Period/ARNT/Singleminded)-GAF (cGMP phosphodiesterase/adenylate cyclase/FhlA) bidomain carrying the chromophore and the smaller PHY (phytochrome-specific) domain. The PHY domain is structurally related to the GAF family, but carries an unusual tongue-like structure which contacts the larger lobe to seal the chromophore pocket. In 2VEA, the tongue makes intimate contact with the helical N-terminus; both the N-terminus and the tongue structures are quite different in 3C2W. As expected, the structures reveal ZUsso and ZZEssa chromophore conformations in 2VEA and 3C2W respectively, associated with tautomeric differences in several nearby tyrosine residues. Two salt bridges on opposite sides of the chromophore, as well as the associations of the C-ring propionates also differ. It is still unclear, however, which of these structural differences are associated with bacteriophytochromes compared with (phi and plant-type phytochromes, the unusual 3C2W Pfr ground state functionality compared with the Pr ground state or the Pr compared with Pfr photoisomerism. To access the latter unambiguously, both Pr and Pfr structures of the same molecule are required. New solid-phase NMR data for (phi in the Pr, Pfr and freeze-trapped intermediate states reveal unexpected changes in the chromophore during Pfr Pr photoconversion. These, together with our efforts to solve the three-dimensional structure of a complete phytochrome molecule are also described.



Citation Styles

Harvard Citation styleHughes, J. (2010) Phytochrome three-dimensional structures and functions, Biochemical Society Transactions, 38(2), pp. 710-716. https://doi.org/10.1042/BST0380710

APA Citation styleHughes, J. (2010). Phytochrome three-dimensional structures and functions. Biochemical Society Transactions. 38(2), 710-716. https://doi.org/10.1042/BST0380710


Last updated on 2025-21-05 at 13:47