Ecdysteroid-phosphate Phosphatase is the first structure of a steroid phosphate phosphotase containing alpha beta folds common to members of the two histidine (2H)-

Phosphatase In biochemistry, a phosphatase is an enzyme that uses water to cleave a phosphoric acid Ester, monoester into a phosphate ion and an Alcohol (chemistry), alcohol. Because a phosphatase enzyme catalysis, catalyzes the hydrolysis of its Substrate ...

superfamily with strong homology to the Suppressor of T-cell receptor signaling-1 (Sts-1 PGM) protein. The putative EPPase PGM active site contains signature residues shared by 2H-phosphatase enzymes, including a conserved

histidine Histidine (symbol His or H) is an essential amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated –NH3+ form under biological conditions), a carboxylic acid group (which is in the de ...

(His80) that acts as a

nucleophile In chemistry, a nucleophile is a chemical species that forms bonds by donating an electron pair. All molecules and ions with a free pair of electrons or at least one pi bond can act as nucleophiles. Because nucleophiles donate electrons, they are ...

during

catalysis Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...

. The physiological substrate ecdysone 22-phosphate was modeled in a hydrophobic cavity close to the phosphate- binding site. EPPase PGM shows limited substrate specificity with an ability to hydrolyze steroid phosphates, the phospho-tyrosine (pTyr) substrate analogue para-nitrophenylphosphate ( pNPP) and pTyr-containing peptides and proteins. It has been shown that new protein tyrosine phosphatase (PTP) activity for EPPase. Also, EPPase and its closest homologues can be grouped into a distinct subfamily in the large 2H-

superfamily of proteins.

Image

Concerning the sequence for EPPase, the following link will display where in the sequence alpha and beta strands can be found. http://www.rcsb.org/pdb/explore/remediatedSequence.do?structureId=3C7T

Studies of EPPase

In some studies, the genes for EPPase were obtained from a silk moth while a strain of Escherichia coli served as the host for production of this receptor. A

plasmid A plasmid is a small, extrachromosomal DNA molecule within a cell that is physically separated from chromosomal DNA and can replicate independently. They are most commonly found as small circular, double-stranded DNA molecules in bacteria; how ...

served as the vector for which this gene was implanted into the E.coli strain.

Structure

The structure of EPPase was obtained by

x-ray diffraction X-ray crystallography is the experimental science determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract into many specific directions. By measuring the angles ...

and the following link provides another picture of the structure. https://www.ncbi.nlm.nih.gov/Structure/mmdb/mmdbsrv.cgi?uid=70358

References

* {{DEFAULTSORT:Ecdysteroid-Phosphate Phosphatase EC 3.1.3 Post-translational modification Hydrolases Enzymes