TY - JOUR
T1 - Photosystem I, an improved model of the stromal subunits PsaC, PsaD, and PsaE
AU - Klukas, Olaf
AU - Schubert, Wolf Dieter
AU - Jordan, Patrick
AU - Krauß, Norbert
AU - Fromme, Petra
AU - Witt, Horst Tobias
AU - Saenger, Wolfram
PY - 1999/3/12
Y1 - 1999/3/12
N2 - An improved electron density map of photosystem I (PSI) calculated at 4- Å resolution yields a more detailed structural model of the stromal subunits PsaC, PsaD, and PsaE than previously reported. The NMR structure of the subunit PsaE of PSI from Synechococcus sp. PCC7002 (Falzone, C. J., Kao, Y.- H., Zhao, J., Bryant, D. A., and Lecomte, J. T. J. (1994) Biochemistry 33, 6052-6062) has been used as a model to interpret the region of the electron density map corresponding to this subunit. The spatial orientation with respect to other subunits is described as well as the possible interactions between the stromal subunits. A first model of PsaD consisting of a four- stranded β-sheet and an α-helix is suggested, indicating that this subunit partly shields PsaC from the stromal side. In addition to the improvements on the stromal subunits, the structural model of the membrane-integral region of PSI is also extended. The current electron density map allows the identification of the N and C termini of the subunits PsaA and PsaB. The 11- transmembrane α-helices of these subunits can now be assigned uniquely to the hydrophobic segments identified by hydrophobicity analyses.
AB - An improved electron density map of photosystem I (PSI) calculated at 4- Å resolution yields a more detailed structural model of the stromal subunits PsaC, PsaD, and PsaE than previously reported. The NMR structure of the subunit PsaE of PSI from Synechococcus sp. PCC7002 (Falzone, C. J., Kao, Y.- H., Zhao, J., Bryant, D. A., and Lecomte, J. T. J. (1994) Biochemistry 33, 6052-6062) has been used as a model to interpret the region of the electron density map corresponding to this subunit. The spatial orientation with respect to other subunits is described as well as the possible interactions between the stromal subunits. A first model of PsaD consisting of a four- stranded β-sheet and an α-helix is suggested, indicating that this subunit partly shields PsaC from the stromal side. In addition to the improvements on the stromal subunits, the structural model of the membrane-integral region of PSI is also extended. The current electron density map allows the identification of the N and C termini of the subunits PsaA and PsaB. The 11- transmembrane α-helices of these subunits can now be assigned uniquely to the hydrophobic segments identified by hydrophobicity analyses.
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U2 - 10.1074/jbc.274.11.7351
DO - 10.1074/jbc.274.11.7351
M3 - Article
C2 - 10066799
AN - SCOPUS:0033548585
VL - 274
SP - 7351
EP - 7360
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 11
ER -