1qx8
From Proteopedia
Crystal structure of a five-residue deletion mutant of the Rop protein
Overview
The repressor of primer (Rop) protein has become a steady source of surprises concerning the relationship between the sequences and the structures of several of its mutants and variants. Here we add another piece to the puzzle of Rop by showing that an engineered deletion mutant of the protein (corresponding to a deletion of residues 30-34 of the wild-type protein and designed to restore the heptad periodicity at the turn region) results in a complete reorganization of the bundle which is converted from a homodimer to a homotetramer. In contrast (and as previously shown), a two-residue insertion, which also restores the heptad periodicity, is essentially identical with wild-type Rop. The new deletion mutant structure is a canonical, left-handed, all-antiparallel bundle with a completely different hydrophobic core and distinct surface properties. The structure agrees and qualitatively explains the results from functional, thermodynamic, and kinetic studies which indicated that this deletion mutant is a biologically inactive hyperstable homotetramer. Additional insight into the stability and dynamics of the mutant structure has been obtained from extensive molecular dynamics simulations in explicit water and with full treatment of electrostatics.
About this Structure
1QX8 is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
Loopless Rop: structure and dynamics of an engineered homotetrameric variant of the repressor of primer protein., Glykos NM, Papanikolau Y, Vlassi M, Kotsifaki D, Cesareni G, Kokkinidis M, Biochemistry. 2006 Sep 12;45(36):10905-19. PMID:16953576 Page seeded by OCA on Sat May 3 06:48:35 2008
