CRYSTAL STRUCTURE REDUCED PUTA86-630 MUTANT Y540S COMPLEXED WITH TRANS-4-HYDROXY-L-PROLINE OXIDOREDUCTASE, PROLINE UTILIZATION A, PUTA, FLAVOENZYME, DNA-BINDING, FAD, FLAVOPROTEIN, MULTIFUNCTIONAL ENZYME, NAD, PROLINE METABOLISM, REPRESSOR, TRANSCRIPTION, TRANSCRIPTION REGULATION 3E2Q