A New Catalytic Mechanism of Periplasmic Nitrate Reductase from Desulfovibrio desulfuricans ATCC 27774 from Crystallographic and EPR Data and based on detailed analysis of the sixth ligand

2-AMINO-5,6-DIMERCAPTO-7-METHYL-3,7,8A,9-TETRAHYDRO-8-OXA-1,3,9,10-TETRAAZA-ANTHRACEN-4-ONE GUANOSINE DINUCLEOTIDE

Periplasmic Nitrate Reductase Revisited: A Sulfur Atom Completes the Sixth Coordination of the Catalytic Molybdenum.

Epr and Redox Properties of Periplasmic Nitrate Reductase from Desulfovibrio Desulfuricans Atcc 27774

ADNRPEKWVKGVCRYCGTGCGVLVGVKDGKAVAIQGNPNNHNAGLLCLKGSLLIPVLNSKERVTQPLVRRHKGGKLEPVS
WDEALDLMASRFRSSIDMYGPNSVAWYGSGQCLTEESYVANKIFKGGFGTNNVDGNPRLCMASAVGGYVTSFGKDEPMGT
YADIDQATCFFIIGSNTSEAHPVLFRRIARRKQVEPGVKIIVADPRRTNTSRIADMHVAFRPGTDLAFMHSMAWVIINEE
LDNPRFWQRYVNFMDAEGKPSDFEGYKAFLENYRPEKVAEICRVPVEQIYGAARAFAESAATMSLWCMGINQRVQGVFAN
NLIHNLHLITGQICRPGATSFSLTGQPNACGGVRDGGALSHLLPAGRAIPNAKHRAEMEKLWGLPEGRIAPEPGYHTVAL
FEALGRGDVKCMIICETNPAHTLPNLNKVHKAMSHPESFIVCIEAFPDAVTLEYADLVLPPAFWCERDGVYGCGERRYSL
TEKAVDPPGQCRPTVNTLVEFARRAGVDPQLVNFRNAEDVWNEWRMVSKGTTYDFWGMTRERLRKESGLIWPCPSEDHPG
TSLRYVRGQDPCVPADHPDRFFFYGKPDGRAVIWMRPAKGAAEEPDAEYPLYLTSMRVIDHWHTATMTGKVPELQKANPI
AFVEINEEDAARTGIKHGDSVIVETRRDAMELPARVSDVCRPGLIAVPFFDPKKLVNKLFLDATDPVSREPEYKICAARV
RKA

COCRYSTALLISATION WITH 10MM OF KCN (CYANIDE) IN 200MM OF DDNAPA (IE PROTEIN) WHICH HAD BEEN REDUCED BY DITHIONITE IN ANAEROBIC CONDITIONS AND THEN AIR REOXIDISED BEFORE SETTTING UP FOR CRYSTALLISATIONS STRAIGHT AFTER THAWING FROM 193K. CRYSTALLISING CONDITIONS IN 0.1M MES PH 6.0, 8% PEG 8000

DISSIMILATORY NITRATE REDUCTASE (NAP) FROM DESULFOVIBRIO DESULFURICANS

SHEET
DETERMINATION METHOD: DSSP
THE SHEETS PRESENTED AS "AG" IN EACH CHAIN ON SHEET RECORDS
BELOW IS ACTUALLY AN 6-STRANDED BARREL THIS IS REPRESENTED BY
A 7-STRANDED SHEET IN WHICH THE FIRST AND LAST STRANDS
ARE IDENTICAL.

ESSENTIAL FUNCTION FOR NITRATE ASSIMILATION

HYDROGENS HAVE BEEN ADDED IN THE RIDING POSITIONS. DISORDERED REGIONS WERE MODELED STEREOCHEMICALLY E.G AMINO ACID SIDE CHAINS WHICH SHOW MOST FLEXIBILITY INCLUDING THE FOLLOWING LYSINES (7, 27, 75, 259, 380, 636, 722), ARGININES (4, 544, 652), GLUTAMATES (6, 257, 287, 386, 541, 608, 647, 648) AND GLUTAMINES (193, 510). SOME OF THESE HAVE BEEN ASSIGNED WITH ALTERNATE CONFORMATIONS.

NITRATE ASSIMILATION, NITROGENOUS ACCEPTOR, IRON, TRANSPORT, MOLYBDENUM, PERIPLASMIC, DISULFIDE BOND, ELECTRON TRANSPORT, IRON-SULFUR, IRON- SULFUR, METAL-BINDING, DISSIMILATORY NITRATE REDUCTASE, MOLYBDOPTERIN COFACTOR, SULFIDO LIGAND, 4FE-4S CLUSTER, OXIDOREDUCTASE, ELECTRON PARAMAGNETIC RESONANCE