INVESTIGADORES
BARRA Jose Luis
congresos y reuniones científicas
Título:
DNA structure/sequence requeriments for Pseudomonas aeruginosa MutL endonuclease activity
Autor/es:
ELISA M.E. CORREA; LUISINA DE TULLIO; PABLO S. VÉLEZ; MARIANA A. MARTINA; CARLOS E. ARGARAÑA; JOSÉ L. BARRA
Lugar:
Mendoza
Reunión:
Congreso; XLVIII Reunión anual SAIB; 2012
Institución organizadora:
SAIB
Resumen:
The hallmark of the mismatch repair system (MRS) in bacterial and
eukaryotic organisms devoid of MutH, is the presence of a MutL homolog
containing endonuclease activity. Our group has recently described that
Pseudomonas aeruginosa MutL (PaMutL) has a cation-dependent
endonuclease activity. In this study, DNA structure/sequence requirements of
PaMutL activity were analyzed. The results showed that PaMutL generated
incisions on supercoiled plasmids, but not on homoduplex or heteroduplex
linear DNA molecules. Furthermore, PaMutL displayed the same endonuclease
activity on highly negative supercoiled and on relaxed plasmids. The fact that
PaMutL was able to generate incisions on plasmids independently of its
supercoiling degree, but not on linear DNA, suggests that PaMutL requires
fixed-ends DNA molecules for its in vitro endonuclease activity. In addition, the
analysis of the incision sites generated on supercoiled plasmids indicated that
PaMutL, as well as Bacillus thuringiensis MutL homolog, has no sequence
specificity.
These results indicate that contrary to MutH, which specifically
recognizes and cleaves GATC sequences, MutL homologs with endonuclease
activity do not require a specific sequence to make an incision. As a
consequence, the MRS in these organisms could be more efficient than in those
with MutH, considering that GATC distribution can affect the MRS efficiency.