Nucleotidyltransferase

Regulation of bacterial glutamine synthase (GlnA) by adenylylation and (indirectly) by uridylylation. Uridylyltransferase (GlnD) uridylylates the regulatory PII protein (GlnB) which determines whether adenylyltransferase (GlnE) adenylylates or de-adenylylates glutamine synthase. GlnD is a bifunctional enzyme that both attaches and removes UMP from GlnB. GlnD is activated by α-ketoglutarate and ATP (green) but inhibited by glutamine and inorganic phosphate (Pi, in red). The protein names are those in E. coli. Homologs in other bacteria may have different names.[1]

Nucleotidyltransferases are transferase enzymes of phosphorus-containing groups, e.g., substituents of nucleotidylic acids or simply nucleoside monophosphates. The general reaction of transferring a nucleoside monophosphate moiety from A to B, can be written as:

A-P-N + B A + B-P-N

For example, in the case of polymerases, A is pyrophosphate and B is the nascent polynucleotide. They are classified under EC number 2.7.7 and they can be categorised into:

  1. Uridylyltransferases, which transfer uridylyl- groups
  2. Adenylyltransferases, which transfer adenylyl- groups
  3. Guanylyltransferases, which transfer guanylyl- groups
  4. Cytitidylyltransferases, which transfer cytidylyl- groups
  5. Thymidylyltransferases, which transfer thymidylyl- groups
  1. ^ Voet D, Voet JG, Pratt CW (2008). Fundamentals of Biochemistry (3rd ed.). John Wiley & Sons, pp. 767