The kinetic mechanism of the unidirectional
H2-oxidizing hydrogenase from soybean nodule bacteroids has
been investigated with highly purified enzyme. Measurements
of the K, for H2 vary from 0.97 to 2.6 pM, and the K,,, for
methylene blue varies from 6 to 17 pM. With H2 and
methylene blue as substrates,...
Carbonyl sulfide (COS) has been investigated as a rapid-equilibrium inhibitor of CO oxidation
by the CO dehydrogenase purified from Rhodospirillum rubrum. The kinetic evidence suggests that the
inhibition by COS is largely competitive versus CO (Ki = 2.3 pM) and uncompetitive versus methylviologen
as electron acceptor (Ki = 15.8 pM)....
The virus-encoded proteins of tobacco etch virus (TEV), a plant potyvirus, arise by proteolytic processing of
a large polyprotein precursor. The TEV genome codes for two proteinases, a 49-kilodalton proteinase and
helper component proteinase (HC-Pro), which cleave the polyprotein at specific sites. The only known cleavage
event catalyzed by HC-Pro...
This scanned article is provided to correct an error on the publisher’s website. The online version has incorrectly given the first author name as “Listen, Aaron” rather than the correct, “Liston, Aaron.” If using this article, please cite the first author correctly.
The RNA genome of tobacco etch virus (TEV), a plant potyvirus, functions as an mRNA for synthesis of a
346-kilodalton polyprotein that undergoes extensive proteolytic processing. The RNA lacks a normal 5' cap
structure at its terminus, which suggests that the mechanism of translational initiation differs from that of a...
The effects of nitric oxide (NO) on the individual components of Azotobacter vinelandii
nitrogenase have been examined by kinetic and spectroscopic methods. Incubation of the Fe protein (Av2)
for 1 h with stoichiometries of 4- and 8-fold molar excesses of NO to Av2 dimer resulted in a complete
loss of...
Acetylene is a slow-binding inhibitor of the Ni- and Fe-containing dimeric hydrogenase isolated
from Azotobacter vinelandii. Acetylene was released from hydrogenase during the recovery from inhibition.
This indicates that no transformation of acetylene to another compound occurred as a result of the interaction
with hydrogenase. However, the release of C2H2...
A genetic complementation system was developed
in which tobacco etch virus (TEV) polymerase (NIb)-
expressing transgenic plants or protoplasts were inoculated
with NIb-defective TEV mutants. A β-glucuronidase (GUS)
reporter gene integrated into the genomes of parental and four
mutant viruses was used to assay RNA amplification. Two
mutants (termed VNN...
Tobacco etch virus (TEV) encodes three proteinases that catalyze processing of the genome-encoded polyprotein.
The P1 proteinase originates from the N terminus of the polyprotein and catalyzes proteolysis between
itself and the helper component proteinase (HC-Pro). Mutations resulting in substitution of a single amino
acid, small insertions, or deletions were...
The tobacco etch potyvirus (TEV) polyprotein is proteolytically processed by three viral proteinases (NIa,
HC-Pro, and P1). While the NIa and HC-Pro proteinases each provide multiple functions essential for viral
infectivity, the role of the P1 proteinase beyond its autoproteolytic activity is understood poorly. To determine
if P1 is necessary...