Crystal structure of muconolactone isomerase at 3.3 A resolution.
The crystal structure of muconolactone isomerase from Pseudomonas putida, a unique molecule with ten 96 amino acid subunits and 5-fold, and 2-fold symmetries, has been solved at 3.3 A resolution. The non-crystallographic symmetries were used to refine the initial single isomorphous replacement phases and produce an interpretable 10-fold averaged map. The backbone trace is complete and confirmed by the amino acid sequence fit. Each subunit is composed of a body with two alpha-helices and an antiparallel twisted beta-sheet of four strands, and an extended arm. The helices and the sheet fold to form a two-layered structure with an enclosed hydrophobic core and a partially formed putative active site pocket. The C-terminal arm of another subunit related by a local dyad symmetry extends over the core to complete this pocket. The decameric protein is almost spherical, with the helices forming the external coat. There is a large hydrophilic cavity in the center with open ends along the 5-fold axis. Molecular interactions between subunits are extensive. Each subunit contacts four neighbors and loses nearly 40% of its solvent contact area on oligomerization.
Katti
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SK
Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511.
Katz
B A
BA
Wyckoff
H W
HW
D000596:Amino Acids; D001426:Bacterial Proteins; D019748:Carbon-Carbon Double Bond Isomerases; D002384:Catalysis; D007535:Isomerases; D008958:Models, Molecular; D008961:Models, Structural; D011108:Polymers; D011549:Pseudomonas / Q000201:enzymology*; D014961:X-Ray Diffraction
D000596:Amino Acids; D001426:Bacterial Proteins; D011108:Polymers; D007535:Isomerases; D019748:Carbon-Carbon Double Bond Isomerases; C100087:muconolactone delta-isomerase