PSCD Domains of Pleuralin-1 from the Diatom Cylindrotheca fusiformis: NMR Structures and Interactions with Other Biosilica-Associated Proteins.
Diatoms are eukaryotic unicellular algae characterized by silica cell walls and associated with three unique protein families, the pleuralins, frustulins, and silaffins. The NMR structure of the PSCD4 domain of pleuralin-1 from Cylindrotheca fusiformis contains only three short helical elements and is stabilized by five unique disulfide bridges. PSCD4 contains two binding sites for Ca(2+) ions with millimolar affinity. NMR-based interaction studies show an interaction of the domain with native silaffin-1A as well as with α-frustulins. The interaction sites of the two proteins mapped on the PSCD4 structure are contiguous and show only a small overlap. A plausible functional role of pleuralin could be to bind simultaneously silaffin-1A located inside the cell wall and α-frustulin coating the cell wall, thus connecting the interfaces between hypotheca and epitheca at the girdle bands. Restrained molecular dynamics calculations suggest a bead-chain-like structure of the central part of pleuralin-1.
Institute of Biophysics und Physical Biochemistry, Centre of Magnetic Resonance in Chemistry and Biomedicine, University of Regensburg, 93040 Regensburg, Germany.
Silvia
S
De Sanctis
Institute of Biophysics und Physical Biochemistry, Centre of Magnetic Resonance in Chemistry and Biomedicine, University of Regensburg, 93040 Regensburg, Germany; Bruker BioSpin AG, 8117 Fällanden, Switzerland.
Michael
M
Wenzler
Institute of Biochemistry, Microbiology and Genetics, University of Regensburg, 93040 Regensburg, Germany; Department of Chemistry and Food Chemistry, B CUBE Center for Molecular Bioengineering, TU Dresden, 01307 Dresden, Germany.
Nils
N
Kröger
Institute of Biophysics und Physical Biochemistry, Centre of Magnetic Resonance in Chemistry and Biomedicine, University of Regensburg, 93040 Regensburg, Germany.
Wilhelm M
WM
Malloni
Institute of Biochemistry, Microbiology and Genetics, University of Regensburg, 93040 Regensburg, Germany.
Manfred
M
Sumper
Institute of Biochemistry, Microbiology and Genetics, University of Regensburg, 93040 Regensburg, Germany.
Rainer
R
Deutzmann
Institute of Biophysics und Physical Biochemistry, Centre of Magnetic Resonance in Chemistry and Biomedicine, University of Regensburg, 93040 Regensburg, Germany.
Patrick
P
Zadravec
Institute of Biophysics und Physical Biochemistry, Centre of Magnetic Resonance in Chemistry and Biomedicine, University of Regensburg, 93040 Regensburg, Germany; Bioanalytical Chemistry, Department of Chemistry and Food Chemistry, TU Dresden, 01062 Dresden, Germany.
Eike
E
Brunner
Institute of Biophysics und Physical Biochemistry, Centre of Magnetic Resonance in Chemistry and Biomedicine, University of Regensburg, 93040 Regensburg, Germany.
Werner
W
Kremer
Institute of Biophysics und Physical Biochemistry, Centre of Magnetic Resonance in Chemistry and Biomedicine, University of Regensburg, 93040 Regensburg, Germany. Electronic address: hans-robert.kalbitzer@biologie.uni-regensburg.de.
Hans Robert
HR
Kalbitzer
D002118:Calcium / Q000378:metabolism; D002473:Cell Wall / Q000737:chemistry*; D017377:Diatoms / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D010455:Peptides / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D000072417:Protein Domains; D012822:Silicon Dioxide / Q000378:metabolism*
D010455:Peptides; C400535:silaffin 1A; D012822:Silicon Dioxide; D002118:Calcium