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Structure, function and evolution of the cyanobacterial orange carotenoid protein and its homologs
Author(s) -
Kerfeld Cheryl A.,
Melnicki Matthew R.,
Sutter Markus,
DominguezMartin Maria Agustina
Publication year - 2017
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.14670
Subject(s) - phycobilisome , carotenoid , synechocystis , effector , singlet oxygen , cyanobacteria , photosynthesis , non photochemical quenching , orange (colour) , quenching (fluorescence) , biology , biophysics , chemistry , photoprotection , fluorescence , photochemistry , biochemistry , photosystem ii , genetics , oxygen , bacteria , physics , organic chemistry , quantum mechanics , horticulture
ContentsSummary 937 I. Introduction 937 II. The structure of the OCP 938 III. OCP function 939 IV. Distribution of OCPs, FRP and domains in cyanobacteria 943 V. Carotenoid–protein interactions in the OCP and the HCPs 947 VI. Conclusions and prospects 948Acknowledgements 948References 949Summary The orange carotenoid protein ( OCP ) is a water‐soluble, photoactive protein involved in thermal dissipation of excess energy absorbed by the light‐harvesting phycobilisomes ( PBS ) in cyanobacteria. The OCP is structurally and functionally modular, consisting of a sensor domain, an effector domain and a keto‐carotenoid. On photoactivation, the OCP converts from a stable orange form, OCP O , to a red form, OCP R . Activation is accompanied by a translocation of the carotenoid deeper into the effector domain. The increasing availability of cyanobacterial genomes has enabled the identification of new OCP families ( OCP 1, OCP 2, OCPX ). The fluorescence recovery protein ( FRP ) detaches OCP 1 from the PBS core, accelerating its back‐conversion to OCP O ; by contrast, other OCP families are not regulated by FRP . N‐terminal domain homologs, the helical carotenoid proteins ( HCP s), have been found among diverse cyanobacteria, occurring as multiple paralogous groups, with two representatives exhibiting strong singlet oxygen ( 1 O 2 ) quenching ( HCP 2, HCP 3) and another capable of dissipating PBS excitation ( HCP 4). Crystal structures are presently available for OCP 1 and HCP 1, and models of other HCP subtypes can be readily produced as a result of strong sequence conservation, providing new insights into the determinants of carotenoid binding and 1 O 2 quenching.