Crystal structures of Leptospira interrogans FAD-containing ferredoxin-NADP+ reductase and its complex with NADP+.
BACKGROUND
Ferredoxin-NADP(H) reductases (FNRs) are flavoenzymes that catalyze the electron transfer between NADP(H) and the proteins ferredoxin or flavodoxin. A number of structural features distinguish plant and bacterial FNRs, one of which is the mode of the cofactor FAD binding. Leptospira interrogans is a spirochaete parasitic bacterium capable of infecting humans and mammals in general. Leptospira interrogans FNR (LepFNR) displays low sequence identity with plant (34% with Zea mays) and bacterial (31% with Escherichia coli) FNRs. However, LepFNR contains all consensus sequences that define the plastidic class FNRs.


RESULTS
The crystal structures of the FAD-containing LepFNR and the complex of the enzyme with NADP+, were solved and compared to known FNRs. The comparison reveals significant structural similarities of the enzyme with the plastidic type FNRs and differences with the bacterial enzymes. Our small angle X-ray scattering experiments show that LepFNR is a monomeric enzyme. Moreover, our biochemical data demonstrate that the LepFNR has an enzymatic activity similar to those reported for the plastidic enzymes and that is significantly different from bacterial flavoenzymes, which display lower turnover rates.


CONCLUSIONS
LepFNR is the first plastidic type FNR found in bacteria and, despite of its low sequence similarity with plastidic FNRs still displays high catalytic turnover rates. The typical structural and biochemical characteristics of plant FNRs unveiled for LepFNR support a notion of a putative lateral gene transfer which presumably offers Leptospira interrogans evolutionary advantages. The wealth of structural information about LepFNR provides a molecular basis for advanced drugs developments against leptospirosis.
Nascimento
Alessandro S
AS
Instituto de Física de São Carlos, Universidade de São Paulo, Av, Trabalhador Saocarlense 400, São Carlos, SP, 13560-970, Brazil. asnascimento@if.sc.usp.br
Catalano-Dupuy
Daniela L
DL
Bernardes
Amanda
A
Neto
Mario de Oliveira
Mde O
Santos
Maria Auxiliadora M
MA
Ceccarelli
Eduardo A
EA
Polikarpov
Igor
I
D000595:Amino Acid Sequence; D001224:Aspartic Acid / Q000737:chemistry; D001419:Bacteria / Q000201:enzymology; D001665:Binding Sites; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000235:genetics; D005287:Ferredoxin-NADP Reductase / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D005182:Flavin-Adenine Dinucleotide / Q000737:chemistry* / Q000378:metabolism*; D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D007921:Leptospira interrogans / Q000201:enzymology*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009249:NADP / Q000378:metabolism*; D010944:Plants / Q000201:enzymology; D011485:Protein Binding; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D053838:Scattering, Small Angle; D017386:Sequence Homology, Amino Acid; D013696:Temperature; D014961:X-Ray Diffraction
D005182:Flavin-Adenine Dinucleotide; D001224:Aspartic Acid; D009249:NADP; D005287:Ferredoxin-NADP Reductase