Structure of the catalytic chain of Methanococcus jannaschii aspartate transcarbamoylase in a hexagonal crystal form: Insights into the path of carbamoyl phosphate to the active site of the enzyme

Journal Article · Tue May 01 04:00:00 EDT 2012 · Acta Crystallographica Section F: Structural Biology and Crystallization Communications

DOI:https://doi.org/10.1107/S1744309112011037· OSTI ID:1046994

Vitali, J; Soares, A; Singh, A K; Colaneri, M J

Crystals of the catalytic chain of Methanococcus jannaschii aspartate transcarbamoylase (ATCase) grew in the presence of the regulatory chain in the hexagonal space group P6{sub 3}22, with one monomer per asymmetric unit. This is the first time that crystals with only one monomer in the asymmetric unit have been obtained; all known structures of the catalytic subunit contain several crystallographically independent monomers. The symmetry-related chains form the staggered dimer of trimers observed in the other known structures of the catalytic subunit. The central channel of the catalytic subunit contains a sulfate ion and a K{sup +} ion as well as a glycerol molecule at its entrance. It is possible that it is involved in channeling carbamoyl phosphate (CP) to the active site of the enzyme. A second sulfate ion near Arg164 is near the second CP position in the wild-type Escherichia coli ATCase structure complexed with CP. It is suggested that this position may also be in the path that CP takes when binding to the active site in a partial diffusion process at 310 K. Additional biochemical studies of carbamoylation and the molecular organization of this enzyme in M. jannaschii will provide further insight into these points.

• Research Organization: BROOKHAVEN NATIONAL LABORATORY (BNL)
• Sponsoring Organization: USDOE SC OFFICE OF BIOLOGICAL & ENVIRONMENTAL RESEARCH
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 1046994
• Report Number(s): BNL--98107-2012-JA; KP1605010
• Journal Information: Acta Crystallographica Section F: Structural Biology and Crystallization Communications, Journal Name: Acta Crystallographica Section F: Structural Biology and Crystallization Communications Journal Issue: 5 Vol. 68; ISSN 1744-3091
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
60 APPLIED LIFE SCIENCES
CHAINS
CHANNELING
DIFFUSION
DIMERS
ENZYMES
ESCHERICHIA COLI
GLYCEROL
MONOMERS
PHOSPHATES
PROTEINS
SPACE GROUPS
SULFATES