Motion in Type-C Inorganic Pyrophosphatase [ppasec]

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Classification [D-h-2]

Structures
1K23
1K20

Description
Structures are from different organisms and have 55.5% identity, but are known to represent distinct conformations. From the abstract to Ahn et al. (JMB 313:797-811): "Structural studies of the type-C PPases from Streptococcus gordonii and Bacillus subtilis reveal a homodimeric structure, with each polypeptide folding into two domains joined by a flexible hinge. The active site, formed at the interface between the N and C-terminal domains, binds two manganese ions approximately 3.6 angstroms apart in a conformation resembling binuclear metal centres found in other hydrolytic enzymes. An activated water molecule bridging the two metal ions is likely poised for nucleophilic attack of the substrate. Importantly, the S. gordonii and B. subtilis enzymes have crystallised in strikingly different conformations. In both subunits of the S. gordonii crystal structure (1.5 angstrom resolution) the C-terminal domain is positioned such that the active site is occluded, with a sulphate ion bound in the active site. In contrast, in the B. subtilis structure (3.0 angstrom resolution) the C-terminal domain is rotated by about 90 degrees, leaving the active site wide open and accessible for substrate binding."

References
S Ahn, A J Milner, K Futterer, M Konopka, M Ilias, T W Young, S A White (2001). The "open" and "closed" structures of the type-C inorganic pyrophosphatases from Bacillus subtilis and Streptococcus gordonii. J Mol Biol, 313:797-811 [Medline info for 11697905]

GO terms associated with structures
Molecular functionpyrophosphatase activity
Cellular componentcytoplasm

Morphs

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Best representative
Morph Morph name Structure #1 Structure #2 Residues
Inorganic pyrophosphatase 1k20 [ A ] 1k23 [ A ] 304

User-submitted morphs
Morph Morph name Structure #1 Structure #2 Residues
576459-18820 Inorganic pyrophosphatase 1k20 [ A ] 1k23 [ A ] 304
332030-5066 Inorganic pyrophosphate 1k23 [ C ] 1k20 [ A ] 310
971858-14535 PPase 1k20 [ A ] 1k23 [ C ] 304
037192-15995 PPiase 1k20 [ A ] 1k23 [ B ] 304


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Copyright 1995-2005 M. Gerstein, W. Krebs, S. Flores, N. Echols, and others
Email: Mark.Gerstein _at_ yale.edu