2k2i
From Proteopedia
NMR Solution structure of the C-terminal domain (T94-Y172) of the human centrin 2 in complex with a repeat sequence of human Sfi1 (R641-T660)
Structural highlights
Function[CETN2_HUMAN] Plays a fundamental role in microtubule-organizing center structure and function. Required for centriole duplication and correct spindle formation. Has a role in regulating cytokinesis and genome stability via cooperation with CALM1 and CEP110.[1] [2] [3] [4] [5] [6] Involved in global genome nucleotide excision repair (GG-NER) by acting as component of the XPC complex. Cooperatively with RAD23B appears to stabilize XPC. In vitro, stimulates DNA binding of the XPC:RAD23B dimer.[7] [8] [9] [10] [11] [12] The XPC complex is proposed to represent the first factor bound at the sites of DNA damage and together with other core recognition factors, XPA, RPA and the TFIIH complex, is part of the pre-incision (or initial recognition) complex. The XPC complex recognizes a wide spectrum of damaged DNA characterized by distortions of the DNA helix such as single-stranded loops, mismatched bubbles or single stranded overhangs. The orientation of XPC complex binding appears to be crucial for inducing a productive NER. XPC complex is proposed to recognize and to interact with unpaired bases on the undamaged DNA strand which is followed by recruitment of the TFIIH complex and subsequent scanning for lesions in the opposite strand in a 5'-to-3' direction by the NER machinery. Cyclobutane pyrimidine dimers (CPDs) which are formed upon UV-induced DNA damage esacpe detection by the XPC complex due to a low degree of structural perurbation. Instead they are detected by the UV-DDB complex which in turn recruits and cooperates with the XPC complex in the respective DNA repair.[13] [14] [15] [16] [17] [18] [SFI1_HUMAN] Plays a role in the dynamic structure of centrosome-associated contractile fibers via its interaction with CETN2.[19] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedCentrin, an EF-hand calcium-binding protein, has been shown to be involved in the duplication of centrosomes, and Sfi1 (Suppressor of fermentation-induced loss of stress resistance protein 1) is one of its centrosomal targets. There are three isoforms of human centrin, but here we only considered centrin 2 (HsCen2). This protein has the ability to bind to any of the approximately 25 repeats of human Sfi1 (hSfi1) with more or less affinity. In this study, we mainly focused on the 17th repeat (R17-hSfi1-20), which presents the highest level of similarity with a well-studied 17-residue peptide (P17-XPC) from human xeroderma pigmentosum complementation group C protein, another centrin target for DNA repair. The only known structure of HsCen2 was resolved in complex with P17-XPC. The 20-residue peptide R17-hSfi1-20 exhibits the motif L8L4W1, which is the reverse of the XPC motif, W1L4L8. Consequently, the dipole of the helix formed by this motif has a reverse orientation. We wished to ascertain the impact of this reversal on the structure, dynamics and affinity of centrin. To address this question, we determined the structure of C-HsCen2 [the C-terminal domain of HsCen2 (T94-Y172)] in complex with R17-hSfi1-20 and monitored its dynamics by NMR, after having verified that the N-terminal domain of HsCen2 does not interact with the peptide. The structure shows that the binding mode is similar to that of P17-XPC. However, we observed a 2 -A translation of the R17-hSfi1-20 helix along its axis, inducing less anchorage in the protein and the disruption of a hydrogen bond between a tryptophan residue in the peptide and a well-conserved nearby glutamate in C-HsCen2. NMR dynamic studies of the complex strongly suggested the existence of an unusual calcium secondary binding mode in calcium-binding loop III, made possible by the uncommon residue composition of this loop. The secondary metal site is only populated at high calcium concentration and depends on the type of bound ligand. Structure, dynamics and thermodynamics of the human centrin 2/hSfi1 complex.,Martinez-Sanz J, Kateb F, Assairi L, Blouquit Y, Bodenhausen G, Abergel D, Mouawad L, Craescu CT J Mol Biol. 2010 Jan 8;395(1):191-204. Epub 2009 Oct 24. PMID:19857500[20] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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Categories: Human | Large Structures | Assairi, L | Blouquit, Y | Craescu, C | Duchambon, P | Martinez-Sanz, J | Mouawad, L | Cell cycle | Cell division | Centrin 2 | Mitosis | Phosphoprotein | Sfi1
