Crystal Structure of Cold-Active Protein-Tyrosine Phosphatase from a Psychrophile, Shewanella sp.

Abstract

The cold-active protein-tyrosine phosphatase (CAPTPase) of a psychrophile, Shewanella sp., shows high catalytic activity below 20 degrees C. The catalytic residue of CAPTPase is histidine, as opposed to the cysteine of known protein-tyrosine phosphatases (PTPases), and the enzyme protein has three amino acid sequences, Asp-Xaa-His, Gly-Asp-Xaa-Xaa-Asp-Arg and Gly-Asn-His-Glu, that are observed in many protein-serine/threonine phosphatases (PS/TPases). We have determined the crystal structures of CAPTPase at 1.82 angstroms and the enzyme bound with a phosphate ion at 1.90 angstroms resolution using X-ray crystallography and the multiple isomorphous replacement method. The final refined models are comprised of 331 amino acid residues, two metal ions, 447 water molecules, and an acetate or phosphate ion in an asymmetric unit. The enzyme protein consists of three beta-sheets, termed Sheet I, Sheet I', and Sheet II, and 14 alpha-helices. The CAPTPase has a different overall structure from known protein-tyrosine phosphatases. The arrangement of two metal ions, a phosphate ion and the adjacent amino acid residues in the catalytic site of CAPTPase is identical to that of PS/TPases. Thus, it was confirmed that the CAPTPase was a novel PTPase with a conformation similar to the catalytic site of PS/TPase. We speculate that the hydrophobic moiety around the catalytic residue of CAPTPase might play an important role in eliciting high activity at low temperature.

A Bacterial Phosphatase-Like Enzyme of the Malaria Parasite Plasmodium falciparum Possesses Tyrosine Phosphatase Activity and Is Implicated in the Regulation of Band 3 Dynamics during Parasite Invasion

“…The lack of a catalytic-site cysteine residue in PfShelph2, in addition to its Mn 2ϩ dependence, suggests that PfShelph2 hydrolyzes phosphotyrosine via a mechanism more similar to that of S/T phosphatases than to that of PTPases. This is in accordance with the mechanism proposed for the previously studied Shewanella phosphotyrosine phosphatase (11).…”

“…Two prokaryote-like Plasmodium phosphatases were found to cluster with a family of bacterial phosphatases termed the Shewanella-like phosphatases (Shelphs) after the first and thus far only characterized enzyme of the family (7,8). Despite clustering as a subgroup of the serine/threonine phosphatase family, the Shewanella phosphotyrosine phosphatase (PTPase) has phosphotyrosine phosphatase activity in vitro (9)(10)(11). In contrast to typical PTPases of eukaryotes, which utilize a catalytic-site cysteine residue, the Shelph PTPase utilizes a catalytic mechanism involving divalent metal cations, which is the mechanism used by other members of the serine/threonine phosphatase family to which it belongs (9)(10)(11).…”

“…Despite clustering as a subgroup of the serine/threonine phosphatase family, the Shewanella phosphotyrosine phosphatase (PTPase) has phosphotyrosine phosphatase activity in vitro (9)(10)(11). In contrast to typical PTPases of eukaryotes, which utilize a catalytic-site cysteine residue, the Shelph PTPase utilizes a catalytic mechanism involving divalent metal cations, which is the mechanism used by other members of the serine/threonine phosphatase family to which it belongs (9)(10)(11). In addition to being present in bacteria and Plasmodium spp., orthologues of pfshelph2 (PlasmoDB ID PF3D7_1206000; Uniprot ID Q8I5Y5) exist in other lower eukaryotes, including Schizosaccharomyces pombe, Leishmania major, Trypanosoma brucei, and Cryptosporidium parvum (5,8).…”

Adenosine monophosphate degradation and inosinic acid accumulation in the shrimp Penaeus japonicus

“…The species of Shewanella identified in our study had different activity, but as there are many different species within the genus, multiple phosphatases are likely. At present, the type(s) of phosphatase(s) in the three species identified in this study are not known, although several studies Murakawa et al 2002;Yasuda et al 2002;Yamaguchi et al 2006;Tsuruta et al 2010) have examined phosphatase production in Shewanella spp. The species of bacteria identified in our study probably produce a phosphatase that degrades AMP to AdR in shrimp.…”

Production of Alkaline Phosphatase From a Facultative Psychrophilic Pseudomonas Sp. Mrlba1 Isolated From Passu Glacier, Pakistan

“…The crystal structure of a cold-active alkaline phosphatase from a psychrophile, Shewanella sp. (SCAP), have been determined by Tsuruta et al (2010). Psychrophiles synthesize cold-active enzymes to sustain their cell cycle, and these enzymes are already used in many biotechnological applications requiring high activity at mild temperatures or fast heat-inactivation rate.…”