TY - JOUR
T1 - Does histidine 332 of the D1 polypeptide ligate the manganese cluster in photosystem II? An electron spin echo envelope modulation study
AU - Debus, R. J.
AU - Campbell, K. A.
AU - Gregor, W.
AU - Li, Z. L.
AU - Burnap, R. L.
AU - Britt, R. D.
PY - 2001/3/27
Y1 - 2001/3/27
N2 - The tetranuclear manganese cluster in photosystem II is ligated by one or more histidine residues, as shown by an electron spin echo envelope modulation (ESEEM) study conducted with [15N]histidine-labeled photosystem II particles isolated from the cyanobacterium Synechocystis sp. strain PCC 6803 [Tang, X.-S., Diner, B. A., Larsen, B. S., Gilchrist, M. L., Jr., Lorigan, G. A., and Britt, R. D. (1994) Proc. Natl. Acad. Sci. U.S.A. 91, 704-708]. One of these residues may be His332 of the D1 polypeptide. Photosystem II particles isolated from the Synechocystis mutant D1-H332E exhibit an altered S2 state multiline EPR signal that has more hyperfine lines and narrower splittings than the corresponding signal in wild-type PSII particles [Debus, R. J., Campbell, K. A., Peloquin, J. M., Pham, D. P., and Britt, R. D. (2000) Biochemistry 39, 470-478]. These D1-H332E PSII particles are also unable to advance beyond an altered S2Yz· state, and the quantum yield for forming the S2 state is very low, corresponding to an 8000-fold slowing of the rate of Mn oxidation by Yz·. These observations are consistent with His332 being close to the Mn cluster and modulating the redox properties of both the Mn cluster and tyrosine Yz. To determine if D1-His332 ligates the Mn cluster, we have conducted an ESEEM study of D1-H332E PSII particles. The histidyl nitrogen modulation observed near 5 MHz in ESEEM spectra of the S2 state multiline EPR signal of wild-type PSII particles is substantially diminished in D1-H332E PSII particles. This result is consistent with ligation of the Mn cluster by D1-His332. However, alternate explanations are possible. These are presented and discussed.
AB - The tetranuclear manganese cluster in photosystem II is ligated by one or more histidine residues, as shown by an electron spin echo envelope modulation (ESEEM) study conducted with [15N]histidine-labeled photosystem II particles isolated from the cyanobacterium Synechocystis sp. strain PCC 6803 [Tang, X.-S., Diner, B. A., Larsen, B. S., Gilchrist, M. L., Jr., Lorigan, G. A., and Britt, R. D. (1994) Proc. Natl. Acad. Sci. U.S.A. 91, 704-708]. One of these residues may be His332 of the D1 polypeptide. Photosystem II particles isolated from the Synechocystis mutant D1-H332E exhibit an altered S2 state multiline EPR signal that has more hyperfine lines and narrower splittings than the corresponding signal in wild-type PSII particles [Debus, R. J., Campbell, K. A., Peloquin, J. M., Pham, D. P., and Britt, R. D. (2000) Biochemistry 39, 470-478]. These D1-H332E PSII particles are also unable to advance beyond an altered S2Yz· state, and the quantum yield for forming the S2 state is very low, corresponding to an 8000-fold slowing of the rate of Mn oxidation by Yz·. These observations are consistent with His332 being close to the Mn cluster and modulating the redox properties of both the Mn cluster and tyrosine Yz. To determine if D1-His332 ligates the Mn cluster, we have conducted an ESEEM study of D1-H332E PSII particles. The histidyl nitrogen modulation observed near 5 MHz in ESEEM spectra of the S2 state multiline EPR signal of wild-type PSII particles is substantially diminished in D1-H332E PSII particles. This result is consistent with ligation of the Mn cluster by D1-His332. However, alternate explanations are possible. These are presented and discussed.
UR - http://www.scopus.com/inward/record.url?scp=0035957275&partnerID=8YFLogxK
U2 - 10.1021/bi002394c
DO - 10.1021/bi002394c
M3 - Article
C2 - 11297437
AN - SCOPUS:0035957275
SN - 0006-2960
VL - 40
SP - 3690
EP - 3699
JO - Biochemistry
JF - Biochemistry
IS - 12
ER -