1ibv
From Proteopedia
| |||||||
| , resolution 2.5Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | , | ||||||
| Gene: | HDCA (Lactobacillus sp.) | ||||||
| Activity: | Histidine decarboxylase, with EC number 4.1.1.22 | ||||||
| Related: | 1PYA, 1HQ6, 1IBT, 1IBU, 1IBW
| ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
STRUCTURE OF THE D53,54N MUTANT OF HISTIDINE DECARBOXYLASE BOUND WITH HISTIDINE METHYL ESTER AT-170 C
Overview
Histidine decarboxylase (HDC) from Lactobacillus 30a converts histidine to histamine, a process that enables the bacteria to maintain the optimum pH range for cell growth. HDC is regulated by pH; it is active at low pH and inactive at neutral to alkaline pH. The X-ray structure of HDC at pH 8 revealed that a helix was disordered, resulting in the disruption of the substrate-binding site. The HDC trimer has also been shown to exhibit cooperative kinetics at neutral pH, that is, histidine can trigger a T-state to R-state transition. The D53,54N mutant of HDC has an elevated Km, even at low pH, indicating that the enzyme assumes the low activity T-state. We have solved the structures of the D53,54N mutant at low pH, with and without the substrate analog histidine methyl ester (HME) bound. Structural analysis shows that the apo-D53,54N mutant is in the inactive or T-state and that binding of the substrate analog induces the enzyme to adopt the active or R-state. A mechanism for the cooperative transition is proposed.
About this Structure
1IBV is a Protein complex structure of sequences from Lactobacillus sp.. Full crystallographic information is available from OCA.
Reference
Structure and cooperativity of a T-state mutant of histidine decarboxylase from Lactobacillus 30a., Worley S, Schelp E, Monzingo AF, Ernst S, Robertus JD, Proteins. 2002 Feb 15;46(3):321-9. PMID:11835507
Page seeded by OCA on Sun Mar 30 21:17:34 2008
