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| CATH domain | Related DB codes (homologues) |
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| 3.40.50.720 | S00543,S00551,S00552,S00553,S00602,S00604,S00605,S00608,S00610,S00625,S00319,S00328,S00329,S00330,S00331,S00332,D00456,D00457,D00458,S00324,S00320,S00325,S00326,S00327,D00459,S00335,S00336,S00334,T00219,S00339,D00513,D00001,D00002,D00003,D00005,D00007,D00008,D00010,D00012,D00017,D00018,D00023,D00027,D00028,D00031,D00032,D00033,D00034,D00035,D00037,D00048,D00071,D00476,D00481,D00482,D00490,D00492,D00494,D00545,D00601,D00603,D00604,D00605,D00615,D00845,D00857,D00858,M00161,M00171,M00210,T00002,T00010,T00011,T00015,T00227,T00247,T00408,T00414,D00827,D00262,D00274,M00035,T00109 | | 3.90.25.10 | D00513,D00601,D00604,D00262,D00274 |
| Enzyme Name | | Swiss-prot | KEGG |
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| P67910 |
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| Protein name | ADP-L-glycero-D-manno-heptose-6-epimerase | ADP-glyceromanno-heptose 6-epimerase |
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| Synonyms | EC 5.1.3.20ADP-L-glycero-beta-D-manno-heptose-6-epimeraseADP-glyceromanno-heptose 6-epimeraseADP-hep 6-epimeraseAGME |
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| KEGG pathways | | MAP code | Pathways |
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| MAP00540 | Lipopolysaccharide biosynthesis |
| Swiss-prot:Accession Number | P67910 |
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| Entry name | HLDD_ECOLI |
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| Activity | ADP-D-glycero-D-manno-heptose = ADP-L-glycero- D-manno-heptose. |
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| Subunit | Homopentamer. |
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| Subcellular location |
|
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| Cofactor | Binds 1 NADP(+) per subunit. NAD(+) can substitute for NADP(+), but enzymatic activity is reduced. |
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| References for Catalytic Mechanism | | References | Sections | No. of steps in catalysis |
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| [3] | p.460 |
| | [4] | Fig.3, Fig.4, p.1655-1656 | 3 | | [7] | Scheme 1, p.8878-8879 |
| | [8] | FIGURE 7, p.5914 |
| | [10] | Fig.3, Fig.6, p.3922-3923 |
| | [11] | Fig.3, p.1340-1341 |
|
| references | | [1] |
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| Comments | CHARACTERIZATION. |
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| Medline ID | 95014184 |
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| PubMed ID | 7929099 |
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| Journal | J Biol Chem |
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| Year | 1994 |
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| Volume | 269 |
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| Pages | 24384-90 |
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| Authors | Ding L, Seto BL, Ahmed SA, Coleman WG Jr |
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| Title | Purification and properties of the Escherichia coli K-12 NAD-dependent nucleotide diphosphosugar epimerase, ADP-L-glycero-D-mannoheptose 6-epimerase. |
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| Related Swiss-prot | P67910 |
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| [2] |
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| Comments | CRYSTALLIZATION. |
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| PubMed ID | 10089470 |
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| Journal | Acta Crystallogr D Biol Crystallogr |
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| Year | 1999 |
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| Volume | 55 |
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| Pages | 685-8 |
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| Authors | Ding L, Zhang Y, Deacon AM, Ealick SE, Ni Y, Sun P, Coleman WG Jr |
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| Title | Crystallization and preliminary X-ray diffraction studies of the lipopolysaccharide core biosynthetic enzyme ADP-L-glycero-D-mannoheptose 6-epimerase from Escherichia coli K-12. |
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| Related Swiss-prot | P67910 |
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| [3] |
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| Comments | X-RAY CRYSTALLOGRAPHY (2.0 ANGSTROMS) OF COMPLEX WITH NADP AND ADP-GLUCOSE, AND SUBUNIT. |
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| PubMed ID | 10896473 |
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| Journal | Structure Fold Des |
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| Year | 2000 |
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| Volume | 8 |
|---|
| Pages | 453-62 |
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| Authors | Deacon AM, Ni YS, Coleman WG Jr, Ealick SE |
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| Title | The crystal structure of ADP-L-glycero-D-mannoheptose 6-epimerase: catalysis with a twist. |
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| Related PDB | 1eq2 |
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| Related Swiss-prot | P67910 |
|---|
| [4] |
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| PubMed ID | 11706991 |
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| Journal | Cell Mol Life Sci |
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| Year | 2001 |
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| Volume | 58 |
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| Pages | 1650-65 |
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| Authors | Allard ST, Giraud MF, Naismith JH |
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| Title | Epimerases: structure, function and mechanism. |
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| [5] |
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| Comments | COFACTOR. |
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| PubMed ID | 11313358 |
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| Journal | J Biol Chem |
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| Year | 2001 |
|---|
| Volume | 276 |
|---|
| Pages | 27329-34 |
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| Authors | Ni Y, McPhie P, Deacon A, Ealick S, Coleman WG Jr |
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| Title | Evidence that NADP+ is the physiological cofactor of ADP-L-glycero-D-mannoheptose 6-epimerase. |
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| Related Swiss-prot | P67910 |
|---|
| [6] |
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| PubMed ID | 12137277 |
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| Journal | Nat Prod Rep |
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| Year | 2002 |
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| Volume | 19 |
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| Pages | 261-77 |
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| Authors | Samuel J, Tanner ME |
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| Title | Mechanistic aspects of enzymatic carbohydrate epimerization. |
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| [7] |
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| PubMed ID | 15264802 |
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| Journal | J Am Chem Soc |
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| Year | 2004 |
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| Volume | 126 |
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| Pages | 8878-9 |
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| Authors | Read JA, Ahmed RA, Morrison JP, Coleman WG Jr, Tanner ME |
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| Title | The mechanism of the reaction catalyzed by ADP-beta-L-glycero-D-manno-heptose 6-epimerase. |
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| [8] |
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| PubMed ID | 15823050 |
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| Journal | Biochemistry |
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| Year | 2005 |
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| Volume | 44 |
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| Pages | 5907-15 |
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| Authors | Morrison JP, Read JA, Coleman WG Jr, Tanner ME |
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| Title | Dismutase activity of ADP-L-glycero-D-manno-heptose 6-epimerase: evidence for a direct oxidation/reduction mechanism. |
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| [9] |
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| PubMed ID | 15932222 |
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| Journal | Org Lett |
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| Year | 2005 |
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| Volume | 7 |
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| Pages | 2457-60 |
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| Authors | Read JA, Ahmed RA, Tanner ME |
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| Title | Efficient chemoenzymatic synthesis of ADP-D-glycero-beta-D-manno-heptose and a mechanistic study of ADP-L-glycero-D-manno-heptose 6-epimerase. |
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| [10] |
|---|
| PubMed ID | 17316025 |
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| Journal | Biochemistry |
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| Year | 2007 |
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| Volume | 46 |
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| Pages | 3916-24 |
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| Authors | Morrison JP, Tanner ME |
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| Title | A two-base mechanism for Escherichia coli ADP-L-glycero-D-manno-heptose 6-epimerase. |
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| [11] |
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| PubMed ID | 20506248 |
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| Journal | Protein Sci |
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| Year | 2010 |
|---|
| Volume | 19 |
|---|
| Pages | 1337-43 |
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| Authors | Kowatz T, Morrison JP, Tanner ME, Naismith JH |
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| Title | The crystal structure of the Y140F mutant of ADP-L-glycero-D-manno-heptose 6-epimerase bound to ADP-beta-D-mannose suggests a one base mechanism. |
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| Related PDB | 2x6t,2x86 |
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| comments | This enzyme is homologous to UDP-glucose 4-epimerase (E.C. 5.1.3.2, D00274 in EzCatDB). This enzyme is a distant homologue of the short-chain dehydrogenase/reductase (SDR) superfamily, which includes Drosophia alcohol dehydrogenase (S00319 in EzCatDB). This enzyme has got a catalytic triad composed of conserved residues, Ser, Tyr, and Lys. The conformation of these residues, compared to that of the NAD molecule, seems to be similar to that of the homologous enzymes. According to the literature [4], [7] & [8], this enzyme catalyzes the following reactions: (A) Hydride transfer from C6" atom of the substrate to NADP(+), forming a ketone intermediate and NADPH: (X) Rotation of the reactive part around the C5"-C6" bond in the intermediate: (B) Hydride transfer from NADPH to the ketone intermediate: Here, between the two hydride transfer reactions, a conformational change of the intermediate would occur to expose the opposite face of carbonyl to the cofactor. Moreover, according to the literature [8], [10] and [11], there are two possible mechanisms, a two base mechanism and a one base mechanism. In the two base mechanism (see [8] and [10]), two distinct sets of general base might be involved in the two hydride transfer reactions. In the (A) reaction, Tyr140 from the catalytic triad might act as a general base, whereas Lys178 might act as a general acid in the (B) reaction (see [10]). In the one base mechanism, Tyr140 from the catalytic triad seems to act as a general base in the (A) reaction, and as a general acid in the (B) reaction. In this mechanism, Tyr140 adjusts its position in response to the rotation of the intermediate (see [11]). Considering the active site of this enzyme (2x6t and 2x86), the one base mechanism is more likely, as Lys178 is too far away from the reactive site. Lys178 is involved in binding of the substrate/intermediate, rather than in catalysis.
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| created | updated |
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| 2004-04-05 | 2011-07-07 |
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