Selective modification of Sendai virus hemagglutinin neuraminidase by pyridoxal 5'-phosphate: evidence for an allosteric modulation of neuraminidase activity.
Incubation of Sendai virus with pyridoxal 5'-phosphate (PLP) causes inhibition of hemolytic activity, a slight reduction of hemagglutinating activity, and an increase in neuraminidase activity. The effects on hemagglutination and neuraminidase are prevented by the presence in the incubation mixture of sialyl lactose, a substrate of hemagglutinin-neuraminidase. Incubation with PLP of the water-soluble enzymatic domain of the neuraminidase has no effect on enzymatic activity, while the allosteric inhibition (Dallocchio et al. (1991) Biochem. Int. 25, 663-668) disappears. Both virus-bound and solubilized neuraminidase are selectively modified by PLP at the lysine-553. Our data suggest that PLP inactivates a previously undetected inhibitory site on the viral neuraminidase, and that a physiological effector is present on the viral envelope.
Bellini
T
T
Istituto di Chimica Biologica, Università di Ferrara, Italy.
Tomasi
M
M
Dallocchio
F
F
D000494:Allosteric Regulation; D000596:Amino Acids / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D015707:HN Protein / Q000737:chemistry / Q000378:metabolism*; D006387:Hemagglutination, Viral; D006801:Humans; D008239:Lysine / Q000378:metabolism; D010222:Parainfluenza Virus 1, Human / Q000201:enzymology*; D011732:Pyridoxal Phosphate / Q000378:metabolism*; D013379:Substrate Specificity
D000596:Amino Acids; D015707:HN Protein; D011732:Pyridoxal Phosphate; D008239:Lysine