Sandbox Reserved 828: Difference between revisions
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The gyrase structure reveals a dimer contact with a grooved concave surface for binding the G segment and a cluster of conserved charged residues surrounding the active-site tyrosines. | The gyrase structure reveals a dimer contact with a grooved concave surface for binding the G segment and a cluster of conserved charged residues surrounding the active-site tyrosines. | ||
The A protein breaks and religates DNA as the DNA cleavage core and the CTD lies on it. GyrA59 is the minimal fragment of the A-subunit which, when complexed with the B-subunit, has DNA-cleavage activity. The carboxy-terminal domain of GyrA is required for the introduction of DNA supercoils. Each GyrA59 monomer is composed of two domains at the head region: one similar to the DNA-binding domain of the catabolite-activator protein (CAP), including the helix–turn–helix (HTH) motif; and a second domain with a/bstructure (the ‘tower’ domain) and a single domain with a helical core at the tail region. Two long helices (a14 anda18) emanate from thiscore and connect, together with the C-terminal helix ( | The A protein breaks and religates DNA as the DNA cleavage core and the CTD lies on it. GyrA59 is the minimal fragment of the A-subunit which, when complexed with the B-subunit, has DNA-cleavage activity. The carboxy-terminal domain of GyrA is required for the introduction of DNA supercoils. Each GyrA59 monomer is composed of two domains at the head region: one similar to the DNA-binding domain of the catabolite-activator protein (CAP), including the helix–turn–helix (HTH) motif; and a second domain with a/bstructure (the ‘tower’ domain) and a single domain with a helical core at the tail region. Two long helices (a14 anda18) emanate from thiscore and connect, together with the C-terminal helix (α19), the head and tail fragments The three connecting helices (α14,α18 and α19) adopt very different conformations, leading to large quaternary movements involving a single hinge-point within the helices and rigid body movements of the head fragments (Fig. 2d).. The tail is structurally conserved although large surface loops emanating from different points give it a different outward appearance | ||
The B protein has the ATPase domain and the Toprim fold on it. Two ATPase domains dimerize to form a closed conformation. The Toprim fold is a Rossmann fold that contains three invariant acidic residues that coordinate magnesium ions involved in DNA cleavage and DNA religation | The B protein has the ATPase domain and the Toprim fold on it. Two ATPase domains dimerize to form a closed conformation. The Toprim fold is a Rossmann fold that contains three invariant acidic residues that coordinate magnesium ions involved in DNA cleavage and DNA religation | ||
