This domain has a compact structure composed of four alpha-helices and two beta-hairpins. Helices alpha-1 and alpha-3 are parallel to each other and antiparallel to helices alpha-2 and alpha-4. This domain targets YopH for secretion from the bacterium and translocation into eukaryotic cells, and has phosphotyrosyl peptide-binding activity, allowing for recognition of p130Cas and paxillin.[6] YopH from Yersinia sp. is essential for pathogenesis, as it allows the bacteria to resist phagocytosis by host macrophages through its ability to dephosphorylate host proteins, thereby interfering with the host signalling process. Yersinia has one of the most active PTP enzymes known. YopH contains a loop of ten amino acids (the WPD loop) that covers the entrance of the active site of the enzyme during substratebinding.[7]
All PTPases carry the highly conservedactive sitemotif C(X)5R (PTP signature motif), employ a common catalytic mechanism, and share a similar core structure made of a central parallel beta-sheet with flanking alpha-helices containing a beta-loop-alpha-loop that encompasses the PTP signature motif.[8] Functional diversity between PTPases is endowed by regulatory domains and subunits.
^Wang WQ, Sun JP, Zhang ZY (2003). "An overview of the protein tyrosine phosphatase superfamily". Curr Top Med Chem. 3 (7): 739–48. doi:10.2174/1568026033452302. PMID12678841.
^Evdokimov AG, Tropea JE, Routzahn KM, Copeland TD, Waugh DS (June 2001). "Structure of the N-terminal domain of Yersinia pestis YopH at 2.0 A resolution". Acta Crystallogr. D. 57 (Pt 6): 793–9. doi:10.1107/s0907444901004875. PMID11375498.
^Khajehpour M, Wu L, Liu S, Zhadin N, Zhang ZY, Callender R (April 2007). "Loop dynamics and ligand binding kinetics in the reaction catalyzed by the Yersinia protein tyrosine phosphatase". Biochemistry. 46 (14): 4370–8. doi:10.1021/bi602335x. PMID17352459.
^Barford D, Das AK, Egloff MP (1998). "The structure and mechanism of protein phosphatases: insights into catalysis and regulation". Annu Rev Biophys Biomol Struct. 27: 133–64. doi:10.1146/annurev.biophys.27.1.133. PMID9646865.