2cfa: Difference between revisions

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==Overview==
==Overview==
By using biochemical and structural analyses, we have investigated the, catalytic mechanism of the recently discovered flavin-dependent, thymidylate synthase ThyX from Paramecium bursaria chlorella virus-1, (PBCV-1). Site-directed mutagenesis experiments have identified several, residues implicated in either NADPH oxidation or deprotonation activity of, PBCV-1 ThyX. Chemical modification by diethyl pyrocarbonate and mass, spectroscopic analyses identified a histidine residue (His53) crucial for, NADPH oxidation and located in the vicinity of the redox active N-5 atom, of the FAD ring system. Moreover, we observed that the conformation of, active site key residues of PBCV-1 ThyX differs from earlier reported ThyX, structures, suggesting structural changes during catalysis. Steady-state, kinetic analyses support a reaction mechanism where ThyX catalysis, proceeds via formation of distinct ternary complexes without formation of, a methyl enzyme intermediate.
By using biochemical and structural analyses, we have investigated the catalytic mechanism of the recently discovered flavin-dependent thymidylate synthase ThyX from Paramecium bursaria chlorella virus-1 (PBCV-1). Site-directed mutagenesis experiments have identified several residues implicated in either NADPH oxidation or deprotonation activity of PBCV-1 ThyX. Chemical modification by diethyl pyrocarbonate and mass spectroscopic analyses identified a histidine residue (His53) crucial for NADPH oxidation and located in the vicinity of the redox active N-5 atom of the FAD ring system. Moreover, we observed that the conformation of active site key residues of PBCV-1 ThyX differs from earlier reported ThyX structures, suggesting structural changes during catalysis. Steady-state kinetic analyses support a reaction mechanism where ThyX catalysis proceeds via formation of distinct ternary complexes without formation of a methyl enzyme intermediate.


==About this Structure==
==About this Structure==
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[[Category: Myllykallio, H.]]
[[Category: Myllykallio, H.]]
[[Category: Skouloubris, S.]]
[[Category: Skouloubris, S.]]
[[Category: Tilbeurgh, H.Van.]]
[[Category: Tilbeurgh, H Van.]]
[[Category: Zhou, C.Z.]]
[[Category: Zhou, C Z.]]
[[Category: CME]]
[[Category: CME]]
[[Category: FAD]]
[[Category: FAD]]
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[[Category: tscp]]
[[Category: tscp]]


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