ARGARAÑA CARLOS ENRIQUE
Congresos y reuniones científicas
Título:
STRUCTURAL ANALYSIS OF THE C-TERMINAL REGION OF ESCHERICHIA COLI MUTS
Autor/es:
MIGUEL, V.; PEZZA, R.J.; ARGARAÑA, C.E.
Lugar:
Rosario
Reunión:
Congreso; SAIB; 2006
Institución organizadora:
SAIB
Resumen:
E. coli MutS, an 853 amino acids (aa) protein, is involved in the postreplicative DNA Mismatch Repair System. This is an oligomeric protein with ATPase activity and capacity to bind to heteroduplex DNA. E. coli MutS exists as dimers and tetramers. It is known that the deletion of the 53 C-terminal aa of MutS impedes tetramer formation and that the replacement of the mutS gene in the E. coli chromosome with this deleted version abolishes mismatch repair. Nevertheless, the exact localization and structure of the C-terminal aa sequence responsible for tetramer formation is not known. Here, we show using circular dichroism that a synthetic peptide that contains the 50 C-terminal aa of the protein is largely a-helical. This result agrees with the secondary structure prediction that shows the presence of two a-helix encompassing aa 823-831 and 839-850 respectively, separated by an apparently unstructured region. We have previously established that disruption of the 839-850 a-helix is sufficient to impair MutS oligomerization. We have constructed several C-terminal point mutated versions of MutS in conserved aa within this region, as well as fusion proteins of the maltose binding protein with different portions of the C-terminal region of MutS, in order to clarify the influence of this region in the oligomerization capacity of the protein.
