BACKGROUND: Various Pseudomonas strains can use L-lactate as their sole carbon source for growth. However, the L-lactate-utilizing enzymes in Pseudomonas have never been identified and further studied. METHODOLOGY/PRINCIPAL FINDINGS: An NAD-independent L-lactate dehydrogenase (L-iLDH) was purified from the membrane fraction of Pseudomonas stutzeri SDM. The enzyme catalyzes the oxidation of L-lactate to pyruvate by using FMN as cofactor. After cloning its encoding gene (lldD), L-iLDH was successfully expressed, purified from a recombinant Escherichia coli strain, and characterized. An lldD mutant of P. stutzeri SDM was constructed by gene knockout technology. This mutant was unable to grow on L-lactate, but retained the ability to grow on pyruvate. CONCLUSIONS/SIGNIFICANCE: It is proposed that L-iLDH plays an indispensable function in Pseudomonas L-lactate utilization by catalyzing the conversion of L-lactate into pyruvate.
BACKGROUND: Various Pseudomonas strains can use L-lactate as their sole carbon source for growth. However, the L-lactate-utilizing enzymes in Pseudomonas have never been identified and further studied. METHODOLOGY/PRINCIPAL FINDINGS: An NAD-independent L-lactate dehydrogenase (L-iLDH) was purified from the membrane fraction of Pseudomonas stutzeri SDM. The enzyme catalyzes the oxidation of L-lactate to pyruvate by using FMN as cofactor. After cloning its encoding gene (lldD), L-iLDH was successfully expressed, purified from a recombinant Escherichia coli strain, and characterized. An lldD mutant of P. stutzeri SDM was constructed by gene knockout technology. This mutant was unable to grow on L-lactate, but retained the ability to grow on pyruvate. CONCLUSIONS/SIGNIFICANCE: It is proposed that L-iLDH plays an indispensable function in PseudomonasL-lactate utilization by catalyzing the conversion of L-lactate into pyruvate.
Authors: C K Stover; X Q Pham; A L Erwin; S D Mizoguchi; P Warrener; M J Hickey; F S Brinkman; W O Hufnagle; D J Kowalik; M Lagrou; R L Garber; L Goltry; E Tolentino; S Westbrock-Wadman; Y Yuan; L L Brody; S N Coulter; K R Folger; A Kas; K Larbig; R Lim; K Smith; D Spencer; G K Wong; Z Wu; I T Paulsen; J Reizer; M H Saier; R E Hancock; S Lory; M V Olson Journal: Nature Date: 2000-08-31 Impact factor: 49.962
Authors: K E Nelson; C Weinel; I T Paulsen; R J Dodson; H Hilbert; V A P Martins dos Santos; D E Fouts; S R Gill; M Pop; M Holmes; L Brinkac; M Beanan; R T DeBoy; S Daugherty; J Kolonay; R Madupu; W Nelson; O White; J Peterson; H Khouri; I Hance; P Chris Lee; E Holtzapple; D Scanlan; K Tran; A Moazzez; T Utterback; M Rizzo; K Lee; D Kosack; D Moestl; H Wedler; J Lauber; D Stjepandic; J Hoheisel; M Straetz; S Heim; C Kiewitz; J A Eisen; K N Timmis; A Düsterhöft; B Tümmler; C M Fraser Journal: Environ Microbiol Date: 2002-12 Impact factor: 5.491