Aromatic structure of tyrosine-92 in the extrinsic PsbU protein of red algal photosystem II is important for its functioning.
PsbU is one of the extrinsic proteins in red algal Photosystem II (PSII) and functions to optimize the availability of Ca(2+) and Cl(-) cofactors for water oxidation. To determine the functional residue of PsbU, we constructed various PsbU mutants from a red alga Cyanidium caldarium and reconstituted these mutants with the red algal PSII. The results revealed that Tyr-92 of PsbU, especially its aromatic ring, was essential for maintaining its function. From the crystal structure of PSII, Tyr-92 is located close to Pro-340 of D1, suggesting that the aromatic ring of Tyr-92 interacts with the CH group of Pro-340 of D1, and this CH/pi interaction is important for the optimal function of the Mn(4)Ca-cluster.
Okumura
Akinori
A
Department of Integrated Sciences in Physics and Biology, College of Humanities and Sciences, Nihon University, Tokyo 156-8850, Japan.
Sano
Masanori
M
Suzuki
Takehiro
T
Tanaka
Hiroyasu
H
Nagao
Ryo
R
Nakazato
Katsuyoshi
K
Iwai
Masako
M
Adachi
Hideyuki
H
Shen
Jian-Ren
JR
Enami
Isao
I
D020418:Algal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D002712:Chlorides / Q000378:metabolism; D008958:Models, Molecular; D009154:Mutation; D010100:Oxygen / Q000378:metabolism; D045332:Photosystem II Protein Complex / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000461:Rhodophyta / Q000235:genetics / Q000378:metabolism*; D014443:Tyrosine / Q000737:chemistry; D014867:Water / Q000378:metabolism
D020418:Algal Proteins; D002712:Chlorides; D045332:Photosystem II Protein Complex; D014867:Water; D014443:Tyrosine; D010100:Oxygen; D002118:Calcium