Slow backbone dynamics of the C-terminal fragment of human centrin 2 in complex with a target peptide probed by cross-correlated relaxation in multiple-quantum NMR spectroscopy.
The C-terminal domain of human centrin 2 (C-HsCen2) strongly binds to P1-XPC, a peptide comprising 17 amino acids with a NWKLLAKGLLIRERLKR sequence. This peptide corresponds to residues N847-R863 of XPC, a protein involved in the recognition of damaged DNA during the initial step of the nucleotide excision repair pathway. The slow internal dynamics of the protein backbone in the C-HsCen-P1-XPC complex was studied by measuring the relaxation rates of zero- and double-quantum coherences involving neighboring pairs of carbonyl 13C and amide 15N nuclei. These relaxation rates, which reflect dynamics on time scales in the range of micro- to milliseconds, vary significantly along the protein backbone. Analysis of the relaxation rates at different CaCl2 concentrations and ionic strengths shows that these slow motions are mainly affected by the binding of a Ca2+ ion to the lower-affinity EF-hand III. Moreover, we discuss the possible functional role of residues that undergo differential exchange in the formation of HsCen homodimers.
Kateb
Fatiha
F
Département de Chimie, associé au CNRS, Ecole Normale Supérieure, 24 Rue Lhomond, 75231 Paris Cedex 05, France.
Abergel
Daniel
D
Blouquit
Yves
Y
Duchambon
Patricia
P
Craescu
Constantin T
CT
Bodenhausen
Geoffrey
G
D002135:Calcium-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000737:chemistry* / Q000378:metabolism; D004249:DNA Damage; D004260:DNA Repair / Q000502:physiology; D006801:Humans; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D013329:Structure-Activity Relationship
C472752:CETN2 protein, human; D002135:Calcium-Binding Proteins; D018797:Cell Cycle Proteins