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Deciphering CAD : Structure and function of a mega‐enzymatic pyrimidine factory in health and disease
Author(s) -
CañoOchoa Francisco,
RamónMaiques Santiago
Publication year - 2021
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1002/pro.4158
Subject(s) - pyrimidine metabolism , biochemistry , carbamoyl phosphate synthetase , enzyme , biology , aspartate carbamoyltransferase , function (biology) , compartmentalization (fire protection) , chemistry , microbiology and biotechnology , allosteric regulation , purine
CAD is a 1.5 MDa particle formed by hexameric association of a 250 kDa protein divided into different enzymatic domains, each catalyzing one of the initial reactions for de novo biosynthesis of pyrimidine nucleotides: glutaminase‐dependent C arbamoyl phosphate synthetase, A spartate transcarbamoylase, and D ihydroorotase. The pathway for de novo pyrimidine synthesis is essential for cell proliferation and is conserved in all living organisms, but the covalent linkage of the first enzymatic activities into a multienzymatic CAD particle is unique to animals. In other organisms, these enzymatic activities are encoded as monofunctional proteins for which there is abundant structural and biochemical information. However, the knowledge about CAD is scarce and fragmented. Understanding CAD requires not only to determine the three‐dimensional structures and define the catalytic and regulatory mechanisms of the different enzymatic domains, but also to comprehend how these domains entangle and work in a coordinated and regulated manner. This review summarizes significant progress over the past 10 years toward the characterization of CAD's architecture, function, regulatory mechanisms, and cellular compartmentalization, as well as the recent finding of a new and rare neurometabolic disorder caused by defects in CAD activities.