Complementation of subunits from different bacterial luciferases. Evidence for the role of the. beta. subunit in the bioluminescent mechanism

Journal Article · Wed Dec 10 00:00:00 EST 1980 · J. Biol. Chem.; (United States)

OSTI ID:7065439

Meighen, E A; Bartlet, I

Complementation of the nonidentical subunits (..cap alpha.. and ..beta..) of luciferases isolated from two different bioluminescent strains, Beneckea harveyi and Photobacterium phosphoreum, has resulted in the formation of a functional hybrid luciferase (..cap alpha../sub h/..beta../sub p/) containing the ..cap alpha.. subunit from B. harveyi luciferase (..cap alpha../sub h/) and the ..beta.. subunit from P. phosphoreum luciferase (..beta../sub p/). The complementation was unidirectional; activity could not be restored by complementing the ..cap alpha.. subunit of P. phosphoreum luciferase with the ..beta.. subunit of B. harveyi luciferase, showing that the subunits from these luciferases were not identical. Kinetic parameters of the hybrid luciferase reflecting the intermediate and later steps of the bioluminescent reaction as well as the overall activity and specificity were essentially identical to the same kinetic parameters for B. harveyi luciferase, the source of the ..cap alpha.. subunit, and quite distinct from those of P. phosphoreum luciferase. However, kinetic parameters that reflected the initial step in the reaction involving interaction of FMNH/sub 2/ and luciferase were altered in the hybrid luciferase compared to both the parental luciferases, the K/sub d/ for FMNH/sub 2/ actually being closer to that observed for the P. phosphoreum luciferase (the source of the ..beta.. subunit). These results provide direct evidence that modification or alteration of the ..beta.. subunit in a dimeric luciferase molecule can affect the kinetic properties and indicates that the ..beta.. subunit plays a functional role in the bioluminescent mechanism. It is proposed that both the ..cap alpha.. and ..beta.. subunits are involved with the initial interaction with FMNH/sub 2/, whereas subsequent steps in the mechanism are dictated exclusively by the ..cap alpha.. subunit and are unaffected by alterations in the ..beta.. subunit.

• Research Organization: McGill Univ., Montreal, Quebec
• OSTI ID: 7065439
• Journal Information: J. Biol. Chem.; (United States), Vol. 255:23
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
COMPLEMENT
BIOCHEMICAL REACTION KINETICS
LUCIFERASE
ENZYME ACTIVITY
BACTERIA
BIOCHEMISTRY
CHEMILUMINESCENCE
DYNAMIC FUNCTION STUDIES
MOLECULAR BIOLOGY
CHEMISTRY
ENZYMES
KINETICS
LUMINESCENCE
MICROORGANISMS
OXIDOREDUCTASES
REACTION KINETICS
550200* - Biochemistry
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