CRYSTAL STRUCTURE OF RECA SUPERFAMILY ATPASE PH0284 FROM PYROCOCCUS HORIKOSHII OT3 STRUCTURAL GENOMICS, UNKNOWN FUNCTION, RECA SUPERFAMILY ATPASE, HEXAMER, X-RAY DIFFRACTION, NPPSFA, NATIONAL PROJECT ON PROTEIN STRUCTURAL AND FUNCTIONAL ANALYSES, RIKEN STRUCTURAL GENOMICS/PROTEOMICS INITIATIVE, RSGI 2DR3