Biomaterial Database

Three-dimensional structures of aspartate carbamoyltransferase from Escherichia coli and of its complex with cytidine triphosphate. 1978

H L Monaco, and J L Crawford, and W N Lipscomb

X-ray diffraction studies to nominal resolutions of 3.0 A for unliganded aspartate carbamolytransferase (EC 2.1.3.2)(R32 crystal symmetry) and of 2.8 A for the complex of aspartate carbamoyltransferase with cytidine triphosphate (P321 crystal symmetry) have yielded traces of the polypeptide chains of the catalytic (C) and regulatory (R) chains in the hexameric C6R6 molecules. The independent molecular structures of the liganded and unliganded forms of the enzyme are very nearly identical. In the regulatory chain there is a CTP-binding domain that interacts with an adjacent regulatory subunit and a zinc-binding domain that interacts with the catalytic subunit. In the catalytic chain a polar domain shows interactions between adjacent pairs of C chains to form each trimer C3 while an equatorial domain shows intramolecular C3--C3 interactions. The active site is at or near the interface between adjacent C chains within the trimers. Probably each active center involves amino acid residues from adjacent C chains.

UI	MeSH Term	Description	Entries
D008958	Models, Molecular	Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.	Molecular Models,Model, Molecular,Molecular Model
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D011487	Protein Conformation	The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).	Conformation, Protein,Conformations, Protein,Protein Conformations
D003570	Cytidine Triphosphate	Cytidine 5'-(tetrahydrogen triphosphate). A cytosine nucleotide containing three phosphate groups esterified to the sugar moiety.	CTP,CRPPP,Magnesium CTP,Mg CTP,Triphosphate, Cytidine
D003597	Cytosine Nucleotides	A group of pyrimidine NUCLEOTIDES which contain CYTOSINE.	Cytidine Phosphates,Nucleotides, Cytosine,Phosphates, Cytidine
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D001221	Aspartate Carbamoyltransferase	An enzyme that catalyzes the conversion of carbamoyl phosphate and L-aspartate to yield orthophosphate and N-carbamoyl-L-aspartate. (From Enzyme Nomenclature, 1992) EC 2.1.3.2.	Aspartate Transcarbamylase,Co(II)-Aspartate Transcarbamoylase,Ni(II)-Aspartate Transcarbamoylase,Carbamoyltransferase, Aspartate,Transcarbamylase, Aspartate
D046911	Macromolecular Substances	Compounds and molecular complexes that consist of very large numbers of atoms and are generally over 500 kDa in size. In biological systems macromolecular substances usually can be visualized using ELECTRON MICROSCOPY and are distinguished from ORGANELLES by the lack of a membrane structure.	Macromolecular Complexes,Macromolecular Compounds,Macromolecular Compounds and Complexes,Complexes, Macromolecular,Compounds, Macromolecular,Substances, Macromolecular