1QGX: X-Ray Structure Of Yeast Hal2p

Citation:
Abstract
The product of the yeast HAL2 gene (Hal2p) is an in vivo target of sodium and lithium toxicity and its overexpression improves salt tolerance in yeast and plants. Hal2p is a metabolic phosphatase which catalyses the hydrolysis of 3'-phosphoadenosine-5'-phosphate (PAP) to AMP. It is, the prototype of an evolutionarily conserved family of PAP phosphatases and the engineering of sodium insensitive enzymes of this group may contribute to the generation of salt-tolerant crops. We have solved the crystal structure of Hal2p in complex with magnesium, lithium and the two products of PAP hydrolysis, AMP and Pi, at 1.6 A resolution. A functional screening of random mutations of the HAL2 gene in growing yeast generated forms of the enzyme with reduced cation sensitivity. Analysis of these mutants defined a salt bridge (Glu238 ellipsis Arg152) and a hydrophobic bond (Va170 ellipsis Trp293) as important framework interactions determining cation sensitivity. Hal2p belongs to a larger superfamily of lithium-sensitive phosphatases which includes inositol monophosphatase. The hydrophobic interaction mutated in Hal2p is conserved in this superfamily and its disruption in human inositol monophosphatase also resulted in reduced cation sensitivity.
PDB ID: 1QGXDownload
MMDB ID: 12808
PDB Deposition Date: 1999/5/10
Updated in MMDB: 2007/10
Experimental Method:
x-ray diffraction
Resolution: 1.6  Å
Source Organism:
Similar Structures:
Biological Unit for 1QGX: monomeric; determined by author
Molecular Components in 1QGX
Label Count Molecule
Protein (1 molecule)
1
3',5'-adenosine Bisphosphatase(Gene symbol: MET22)
Molecule annotation
Chemicals (6 molecules)
1
2
2
1
3
1
4
1
5
1
* Click molecule labels to explore molecular sequence information.

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