ISOMERASE, AFE_0303, PUTATIVE SUGAR PHOSPHATE ISOMERASE, STRUCTURAL GENOMICS, JOINT CENTER FOR STRUCTURAL GENOMICS, JCSG, PROTEIN STRUCTURE INITIATIVE, PSI-2 3L2H CRYSTAL STRUCTURE OF PUTATIVE SUGAR PHOSPHATE ISOMERASE (AFE_0303) FROM ACIDITHIOBACILLUS FERROOXIDANS ATCC 23270 AT 1.85 A RESOLUTION