From Genome to Structure and Back Again: A Family Portrait of the Transcarbamylases.
Enzymes in the transcarbamylase family catalyze the transfer of a carbamyl group from carbamyl phosphate (CP) to an amino group of a second substrate. The two best-characterized members, aspartate transcarbamylase (ATCase) and ornithine transcarbamylase (OTCase), are present in most organisms from bacteria to humans. Recently, structures of four new transcarbamylase members, N-acetyl-L-ornithine transcarbamylase (AOTCase), N-succinyl-L-ornithine transcarbamylase (SOTCase), ygeW encoded transcarbamylase (YTCase) and putrescine transcarbamylase (PTCase) have also been determined. Crystal structures of these enzymes have shown that they have a common overall fold with a trimer as their basic biological unit. The monomer structures share a common CP binding site in their N-terminal domain, but have different second substrate binding sites in their C-terminal domain. The discovery of three new transcarbamylases, l-2,3-diaminopropionate transcarbamylase (DPTCase), l-2,4-diaminobutyrate transcarbamylase (DBTCase) and ureidoglycine transcarbamylase (UGTCase), demonstrates that our knowledge and understanding of the spectrum of the transcarbamylase family is still incomplete. In this review, we summarize studies on the structures and function of transcarbamylases demonstrating how structural information helps to define biological function and how small structural differences govern enzyme specificity. Such information is important for correctly annotating transcarbamylase sequences in the genome databases and for identifying new members of the transcarbamylase family.
Center for Genetic Medicine Research, Children's National Medical Center, the George Washington University, Washington, DC 20010, USA. dshi@childrensnational.org.|Department of Integrative Systems Biology, Children's National Medical Center, the George Washington University, Washington, DC 20010, USA. dshi@childrensnational.org.
Dashuang
D
Shi
Department of Cell Biology and Molecular Genetics, College of Computer, Mathematical, and Natural Sciences, University of Maryland, College Park, MD 20742, USA. allewell@umd.edu.|Department of Chemistry and Biochemistry, College of Computer, Mathematical, and Natural Sciences, University of Maryland, College Park, MD 20742, USA. allewell@umd.edu.
Norma M
NM
Allewell
Center for Genetic Medicine Research, Children's National Medical Center, the George Washington University, Washington, DC 20010, USA. mtuchman@childrensnational.org.|Department of Integrative Systems Biology, Children's National Medical Center, the George Washington University, Washington, DC 20010, USA. mtuchman@childrensnational.org.
Mendel
M
Tuchman
D000595:Amino Acid Sequence; D019878:Carboxyl and Carbamoyl Transferases / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D002384:Catalysis; D020134:Catalytic Domain; D030541:Databases, Genetic; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D054730:Protein Interaction Domains and Motifs; D055503:Protein Multimerization; D016415:Sequence Alignment; D013379:Substrate Specificity
D019878:Carboxyl and Carbamoyl Transferases
agamatine deiminase pathway; arginine biosynthesis; arginine deiminase pathway; padanamide biosynthesis; pyrimidine biosynthesis; transcarbamylase; viomycin biosynthesis; zwittermicin A biosynthesis