1cbu
From Proteopedia
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|PDB= 1cbu |SIZE=350|CAPTION= <scene name='initialview01'>1cbu</scene>, resolution 2.3Å | |PDB= 1cbu |SIZE=350|CAPTION= <scene name='initialview01'>1cbu</scene>, resolution 2.3Å | ||
|SITE= | |SITE= | ||
| - | |LIGAND= <scene name='pdbligand=SO4:SULFATE ION'>SO4</scene> | + | |LIGAND= <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene> |
|ACTIVITY= | |ACTIVITY= | ||
|GENE= | |GENE= | ||
| + | |DOMAIN= | ||
| + | |RELATEDENTRY= | ||
| + | |RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1cbu FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1cbu OCA], [http://www.ebi.ac.uk/pdbsum/1cbu PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1cbu RCSB]</span> | ||
}} | }} | ||
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[[Category: Thomas, M G.]] | [[Category: Thomas, M G.]] | ||
[[Category: Thompson, T B.]] | [[Category: Thompson, T B.]] | ||
| - | [[Category: SO4]] | ||
[[Category: adenosylcobinamide]] | [[Category: adenosylcobinamide]] | ||
[[Category: atpase]] | [[Category: atpase]] | ||
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[[Category: transferase]] | [[Category: transferase]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 19:18:36 2008'' |
Revision as of 16:18, 30 March 2008
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| , resolution 2.3Å | |||||||
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| Ligands: | |||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
ADENOSYLCOBINAMIDE KINASE/ADENOSYLCOBINAMIDE PHOSPHATE GUANYLYLTRANSFERASE (COBU) FROM SALMONELLA TYPHIMURIUM
Overview
The X-ray structure of adenosylcobinamide kinase/adenosylcobinamide phosphate guanylyltransferase (CobU) from Salmonella typhimurium has been determined to 2.3 A resolution. This enzyme of subunit molecular weight 19 770 plays a central role in the assembly of the nucleotide loop for adenosylcobalamin where it catalyzes both the phosphorylation of the 1-amino-2-propanol side chain of the corrin ring and the subsequent attachment of GMP to form the product adenosylcobinamide-GDP. The kinase activity is believed to be associated with a P-loop motif, whereas the transferase activity proceeds at a different site on the enzyme via a guanylyl intermediate. The enzyme was crystallized in the space group C2221 with unit cell dimensions of a = 96.4 A, b = 114.4 A, and c = 106.7 A, with three subunits per asymmetric unit. The structure reveals that the enzyme is a molecular trimer and appears somewhat like a propeller with overall molecular dimensions of approximately 64 A x 77 A x 131 A. Each subunit consists of a single domain that is dominated by a seven-stranded mixed beta-sheet flanked on either side by a total of five alpha-helices and one helical turn. Six of the seven beta-strands run parallel. The C-terminal strand lies at the edge of the sheet and runs antiparallel to the others. Interestingly, CobU displays a remarkable structural and topological similarity to the central domain of the RecA protein, although the reason for this observation is unclear. The structure contains a P-loop motif located at the base of a prominent cleft formed by the association of two subunits and is most likely the kinase active site. Each subunit of CobU contains a cis peptide bond between Glu80 and Cys81 where Glu80 faces the P-loop and might serve to coordinate the magnesium ion of the triphosphate substrate. Interestingly, His46, which is the putative site for guanylylation, lies approximately 21 A from the P-loop and is solvent-exposed. This suggests that the enzyme undergoes a conformational change when the substrates bind to bring these two active sites into closer proximity.
About this Structure
1CBU is a Single protein structure of sequence from Salmonella typhimurium. Full crystallographic information is available from OCA.
Reference
Three-dimensional structure of adenosylcobinamide kinase/adenosylcobinamide phosphate guanylyltransferase from Salmonella typhimurium determined to 2.3 A resolution,., Thompson TB, Thomas MG, Escalante-Semerena JC, Rayment I, Biochemistry. 1998 May 26;37(21):7686-95. PMID:9601028
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