Abstract
Dehydroquinate dehydratase (DHQD) catalyzes the third step in the biosynthetic shikimate pathway. Here we identify a Bifidobacterium longum protein with high sequence homology to type II DHQDs but no detectable DHQD activity under standard assay conditions. A crystal structure reveals that the B. longum protein adopts a DHQD-like tertiary structure but a distinct quaternary state. Apparently forming a dimer, the B. longum protein lacks the active site aspartic acid contributed from a neighboring protomer in the type II DHQD dodecamer. Relating to the absence of protein-protein interactions established in the type II DHQD dodecameric assembly, substantial conformational changes distinguish the would-be active site of the B. longum protein. As B. longum possess no other genes with homology to known DHQDs, these findings imply a unique DHQD activity within B. longum.
Original language | English (US) |
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Pages (from-to) | 25-30 |
Number of pages | 6 |
Journal | Journal of Structural and Functional Genomics |
Volume | 14 |
Issue number | 1 |
DOIs | |
State | Published - Mar 2013 |
Externally published | Yes |
Keywords
- Post-translational activation
- Quaternary structure
- Shikimate pathway
- Structural genomics
- X-ray crystal structure
ASJC Scopus subject areas
- Structural Biology
- Biochemistry
- Genetics