Fig. 1.

Alignment of candidate cyclic nucleotide binding proteins with known CNB domains. Representative CNB domains were obtained from Interpro (IPR000595) including those from human (Hs) protein kinases PKA1α, PKG1; channels HCN1, CNGCα1, CNGCβ1; and guanine nucleotide exchange factors EPAC1, EPAC2 and E. coli (Ec) transcription factor CAP. Where the protein has tandem CNB domains these are indicated by the letters “a” and “b”. The number in parenthesis indicates the number of amino acids that have been omitted. The * indicates conserved amino acids across species. Tyrosine residues that have been circled are sites of Y-nitration. The Arabidopsis CNBP candidates PGK1, GAPB, TKL, SHMT1 and PORB align with the CNB domain. The site of Y-nitration in the CNBP candidate, TKL is found within the CNB domain although it is distant from the Y-nitration site in human PKG