PRIMARY SEQUENCE AND REFINED TERTIARY STRUCTURE OF PSEUDOMONAS-FLUORESCENS HOLE AZURIN AT 2.05 ANGSTROM

This paper reports the primary sequence and refined crystal structure of Pseudomonas fluorescens holoazurin. The crystal structure has been determined by molecular replacement on the basis of the molecular mode l of azurin from Alcaligenes denitrificans, and refined by the method of molecular dynamics simulation and energy-restrained least-squares m ethods. P. fluorescens was crystallized in the orthorhombic space grou p P2(1)2(1)2(1) with unit-cell dimensions a = 31.95, b = 43.78, c = 78 .81 Angstrom. The asymmetric unit is composed of only one molecule. Th e final R value is 16.7% for 6691 reflections to a resolution of 2.05 Angstrom. This azurin structure shows some interesting features at His 35 and His83. part of the main chain of strand 3 including His35 O are involved in the contact between two symmetrically related molecules. P. fluorescens is also compared with the other azurin structures in te rms of primary sequence, crystal packing, solvent structure and Cu-sit e geometry. The difference in fluorescence decay behavior of two holoa zurins from P. fluorescens and P. aeruginosa and the correlation betwe en the fluorescence quenching and electron transfer are discussed.