|Gene:||rhaB||Accession Numbers: EG11868 (EcoCyc), b3904, ECK3897|
L-rhamnulose kinase catalyzes the second step of rhamnose degradation, the phosphorylation of rhamnulose.
The substrate spectrum of L-rhamnulose kinase has been investigated; the enzyme shows a broad tolerance for structural modifications of the natural substrate [Fessner92]. Rare sugars have been modeled into the active center of the crystal structure [Grueninger07].
L-rhamnulose kinase is a monomer in solution [Grueninger06]. Crystal structures of L-rhamnulose kinase as an apo- and holo-enzyme as well as the ternary complex including the sugar have been determined and show that the enzyme belongs to the hexokinase-hsp70-actin superfamily. A catalytic mechanism has been proposed [Grueninger06].
A mutated form of RhaB has been shown to also phosphorylate L-xylulose to L-xylulose 1-phosphate and to allow growth of E. coli on L-lyxose [Badia91].
The enzyme was first identified in E. coli B [Wilson57].
rhaB mutants are unable to utilize rhamnose as a source of carbon [Power67].
|Map Position: [4,094,002 <- 4,095,471] (88.24 centisomes, 318°)||Length: 1470 bp / 489 aa|
Molecular Weight of Polypeptide: 54.069 kD (from nucleotide sequence), 52 kD (experimental) [Badia89 ]
Unification Links: ASAP:ABE-0012738 , CGSC:291 , EchoBASE:EB1814 , EcoGene:EG11868 , EcoliWiki:b3904 , ModBase:P32171 , OU-Microarray:b3904 , PortEco:rhaB , PR:PRO_000023734 , Pride:P32171 , Protein Model Portal:P32171 , RefSeq:NP_418340 , RegulonDB:EG11868 , SMR:P32171 , String:511145.b3904 , UniProt:P32171
Relationship Links: InterPro:IN-FAMILY:IPR013449 , InterPro:IN-FAMILY:IPR018484 , InterPro:IN-FAMILY:IPR018485 , PDB:Structure:2CGJ , PDB:Structure:2CGK , PDB:Structure:2CGL , Pfam:IN-FAMILY:PF00370 , Pfam:IN-FAMILY:PF02782
|Biological Process:||GO:0019301 - rhamnose catabolic process
[UniProtGOA12, GOA01a, Chiu64, Power67]
GO:0046835 - carbohydrate phosphorylation [GOA06, GOA01, GOA01a, Grueninger06]
GO:0005975 - carbohydrate metabolic process [GOA01a]
GO:0016310 - phosphorylation [UniProtGOA11a, Gaudet10]
GO:0019299 - rhamnose metabolic process [UniProtGOA11a, GOA06]
|Molecular Function:||GO:0005524 - ATP binding
GO:0008993 - rhamnulokinase activity [GOA06, GOA01, GOA01a, Grueninger06, Fessner92]
GO:0000166 - nucleotide binding [UniProtGOA11a]
GO:0016301 - kinase activity [UniProtGOA11a]
GO:0016740 - transferase activity [UniProtGOA11a]
GO:0016773 - phosphotransferase activity, alcohol group as acceptor [GOA01a]
|Cellular Component:||GO:0005737 - cytoplasm
GO:0005829 - cytosol [DiazMejia09]
|MultiFun Terms:||metabolism → carbon utilization → carbon compounds|
Enzymatic reaction of: L-rhamnulose kinase
Synonyms: rhamnulokinase, ATP:L-rhamnulose 1-phosphotransferase, RhuK
EC Number: 18.104.22.168
The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction of enzyme catalysis.
The reaction is physiologically favored in the direction shown.
Crude extracts were assayed from E. coli B [Wilson57]. The enzyme was partially purified from E. coli K40 [Chiu64] and B [Takagi64] and purified from an unidentified strain of E. coli [Fessner92].
pH(opt): 8.5 [Chiu64]
|Feature Class||Location||Attached Group||Citations||Comment|
|Nucleotide-Phosphate-Binding-Region||13 -> 17||ATP|
|Protein-Segment||236 -> 238|
|Sequence-Conflict||388 -> 389|
10/20/97 Gene b3904 from Blattner lab Genbank (v. M52) entry merged into EcoCyc gene EG11868; confirmed by SwissProt match.
Badia91: Badia J, Gimenez R, Baldoma L, Barnes E, Fessner WD, Aguilar J (1991). "L-lyxose metabolism employs the L-rhamnose pathway in mutant cells of Escherichia coli adapted to grow on L-lyxose." J Bacteriol 1991;173(16);5144-50. PMID: 1650346
DiazMejia09: Diaz-Mejia JJ, Babu M, Emili A (2009). "Computational and experimental approaches to chart the Escherichia coli cell-envelope-associated proteome and interactome." FEMS Microbiol Rev 33(1);66-97. PMID: 19054114
Moralejo93: Moralejo P, Egan SM, Hidalgo E, Aguilar J (1993). "Sequencing and characterization of a gene cluster encoding the enzymes for L-rhamnose metabolism in Escherichia coli." J Bacteriol 175(17);5585-94. PMID: 8396120
Holcroft00: Holcroft CC, Egan SM (2000). "Roles of cyclic AMP receptor protein and the carboxyl-terminal domain of the alpha subunit in transcription activation of the Escherichia coli rhaBAD operon." J Bacteriol 182(12);3529-35. PMID: 10852886
Holcroft00a: Holcroft CC, Egan SM (2000). "Interdependence of activation at rhaSR by cyclic AMP receptor protein, the RNA polymerase alpha subunit C-terminal domain, and rhaR." J Bacteriol 2000;182(23);6774-82. PMID: 11073923
Wickstrum05: Wickstrum JR, Santangelo TJ, Egan SM (2005). "Cyclic AMP receptor protein and RhaR synergistically activate transcription from the L-rhamnose-responsive rhaSR promoter in Escherichia coli." J Bacteriol 187(19);6708-18. PMID: 16166533
Wickstrum07: Wickstrum JR, Skredenske JM, Kolin A, Jin DJ, Fang J, Egan SM (2007). "Transcription activation by the DNA-binding domain of the AraC family protein RhaS in the absence of its effector-binding domain." J Bacteriol 189(14);4984-93. PMID: 17513476
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