Backbone assignment and secondary structure of the PsbQ protein from photosystem II.
PsbQ is one of the extrinsic proteins situated on the lumenal surface of photosystem II (PSII) in the higher plants and green algae. Its three-dimensional structure was determined by X-ray crystallography with exception of the residues 14-33. To obtain further details about its structure and potentially its dynamics, we approached the problem by NMR. In this paper we report (1)H, (15)N, and (13)C NMR assignments for the PsbQ protein. The very challenging oligo-proline stretches could be assigned using (13)C-detected NMR experiments that enabled the assignments of twelve out of the thirteen proline residues of PsbQ. The identification of PsbQ secondary structure elements on the basis of our NMR data was accomplished with the programs TALOS+, web server CS23D and CS-Rosetta. To obtain additional secondary structure information, three-bond H(N)-H(α) J-coupling constants and deviation of experimental (13)C(α) and (13)C(β) chemical shifts from random coil values were determined. The resulting "consensus" secondary structure of PsbQ compares very well with the resolved regions of the published X-ray crystallographic structure and gives a first estimate of the structure of the "missing link" (i.e. residues 14-33), which will serve as the basis for the further investigation of the structure, dynamics and interactions.
Institute of Organic Chemistry, Johannes Kepler University, Altenbergerstraße 69, 4040, Linz, Austria.
Michaela
M
Horničáková
Jaroslava
J
Kohoutová
Judith
J
Schlagnitweit
Christian
C
Wohlschlager
Rüdiger
R
Ettrich
Radovan
R
Fiala
Wolfgang
W
Schoefberger
Norbert
N
Müller
D000595:Amino Acid Sequence; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D045332:Photosystem II Protein Complex / Q000737:chemistry*; D010940:Plant Proteins / Q000737:chemistry*; D011994:Recombinant Proteins / Q000737:chemistry; D018724:Spinacia oleracea / Q000737:chemistry
D045332:Photosystem II Protein Complex; D010940:Plant Proteins; D011994:Recombinant Proteins