InterPro domain: IPR014710

RmlC (deoxythymidine diphosphates-4-dehydrorhamnose 3,5-epimerase; 5.1.3.13 ) is a mainly beta class protein with a jelly roll-like topology. It is a dTDP-sugar isomerase enzyme involved in the synthesis of L-rhamnose, a saccharide required for the virulence of some pathogenic bacteria [ 1 ]. This entry represents the domain with the jelly roll-like fold.

Other protein families containing this domain include glucose-6-phosphate isomerase ( 5.3.1.9 ); germin, a metal-binding protein with oxalate oxidase and superoxide dismutases activities [ 2 ]; auxin-binding protein [ 3 ]; seed storage protein 7S [ 4 ]; acireductone dioxygenase [ 5 ]; as well as three proteins that have metal-binding sites similar to that of germine, namely quercetin 2,3-dioxygenase ( 1.13.11.24 ) [ 6 ], phosphomannose isomerase ( 5.3.1.8 ) [ 7 ] and homogentisate dioxygenase ( 1.13.11.5 ) [ 8 ], the last three sharing a 2-domain fold with storage protein 7s.

The cAMP-binding domains found in the cAMP receptor protein (CRP) family display a similar beta-roll architecture consisting of eight antiparallel beta-strands and three helical segments [ 9 ]. These proteins include CooA, a CO-sensing haem protein that functions as a transcription activator [ 10 ], and the CnbD (cyclic nucleotide binding domain) of the HCN cation channel in which cAMP binding modulates gating of the channel [ 11 ].

1. RmlC, the third enzyme of dTDP-L-rhamnose pathway, is a new class of epimerase. Nat. Struct. Biol. 7, 398-402
2. Germin is a manganese containing homohexamer with oxalate oxidase and superoxide dismutase activities. Nat. Struct. Biol. 7, 1036-40
3. Crystal structure of auxin-binding protein 1 in complex with auxin. EMBO J. 21, 2877-85
4. Crystal structure of soybean proglycinin A1aB1b homotrimer. J. Mol. Biol. 305, 291-305
5. Modeling and experiment yields the structure of acireductone dioxygenase from Klebsiella pneumoniae. Nat. Struct. Biol. 9, 966-72
6. Crystal structure of the copper-containing quercetin 2,3-dioxygenase from Aspergillus japonicus. Structure 10, 259-68
7. The x-ray crystal structure of phosphomannose isomerase from Candida albicans at 1.7 angstrom resolution. Nat. Struct. Biol. 3, 470-9
8. Crystal structure of human homogentisate dioxygenase. Nat. Struct. Biol. 7, 542-6
9. Structure of the CO sensing transcription activator CooA. Nat. Struct. Biol. 7, 876-80
10. Transcription activation by CooA, the CO-sensing factor from Rhodospirillum rubrum. The interaction between CooA and the C-terminal domain of the alpha subunit of RNA polymerase. J. Biol. Chem. 274, 10840-5
11. cAMP Modulation of the cytoplasmic domain in the HCN2 channel investigated by molecular simulations. Biophys. J. 90, 3428-33