Figure 5.
Figure 5 A possible DNA clamp model for RecR. (A) Comparison of
DR RecR with DNA clamp proteins. Ribbon diagrams and
electrostatic potential at the molecular surface are shown for
DR RecR, E. coli DNA polymerase III subunit,
T4 gp45 and human PCNA. The diameter of the central hole is
about 30 -35 Å for DR RecR and about 35 Å for other clamp
proteins. The molecular surface was colored according to the
electrostatic potential: blue, 10 kT; white, 0 kT; red, -10 kT.
(B) Conserved residues of DR RecR located in the putative
DNA-binding region of the central hole (left). Strictly
conserved residues are colored in green and semiconserved
residues in yellow, as deduced by aligning 14 RecR sequences in
Figure 1. Negatively charged residues of the Toprim domain and
the Walker B motif that may play a role in Mg2+-enhanced DNA
binding (right). (C) Model for dsDNA binding by DR RecR.
subunit,
T4 gp45 and human PCNA. The diameter of the central hole is
about 30 -35 Å for DR RecR and about 35 Å for other clamp
proteins. The molecular surface was colored according to the
electrostatic potential: blue, 10 kT; white, 0 kT; red, -10 kT.
(B) Conserved residues of DR RecR located in the putative
DNA-binding region of the central hole (left). Strictly
conserved residues are colored in green and semiconserved
residues in yellow, as deduced by aligning 14 RecR sequences in
Figure 1. Negatively charged residues of the Toprim domain and
the Walker B motif that may play a role in Mg2+-enhanced DNA
binding (right). (C) Model for dsDNA binding by DR RecR.