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M9490367.TXT
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1994-09-19
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Document 0367
DOCN M9490367
TI Kinetics and mechanism of autoprocessing of human immunodeficiency virus
type 1 protease from an analog of the Gag-Pol polyprotein.
DT 9411
AU Louis JM; Nashed NT; Parris KD; Kimmel AR; Jerina DM; Laboratory of
Cellular and Developmental Biology, National; Institute of Diabetes and
Digestive and Kidney Diseases, National; Institutes of Health, Bethesda,
MD 20892.
SO Proc Natl Acad Sci U S A. 1994 Aug 16;91(17):7970-4. Unique Identifier :
AIDSLINE MED/94336669
AB Upon renaturation, the polyprotein MBP-delta TF-Protease-delta Pol,
consisting of HIV-1 protease and short native sequences from the
trans-frame protein (delta TF) and the polymerase (delta Pol) fused to
the maltose-binding protein (MBP) of Escherichia coli, undergoes
autoprocessing to produce the mature protease in two steps. The initial
step corresponds to cleavage of the N-terminal sequence to release the
protein intermediate Protease-delta Pol, which has enzymatic activity
comparable to that of the mature enzyme. Subsequently, the mature enzyme
is formed by a slower cleavage at the C terminus. The rate of increase
in enzymatic activity is identical to that of the appearance of
MBP-delta TF and the disappearance of the MBP-delta TF-Protease-delta
Pol. Initial rates are linearly dependent on the protein concentration,
indicating that the N-terminal cleavage is first-order in protein
concentration. The reaction is competitively inhibited by pepstatin A
and has a pH rate profile similar to that of the mature enzyme. These
results and molecular modeling studies are discussed in terms of a
mechanism in which a dimeric full-length fusion protein must form prior
to rate-limiting intramolecular cleavage of the N-terminal sequence that
leads to an increase in enzymatic activity.
DE Amino Acid Sequence Carrier Proteins/BIOSYNTHESIS Escherichia
coli/METABOLISM Fusion Proteins, gag-pol/*METABOLISM Hydrogen-Ion
Concentration HIV Protease/*BIOSYNTHESIS/CHEMISTRY/METABOLISM
HIV-1/*ENZYMOLOGY Kinetics Models, Molecular Molecular Sequence Data
Oligopeptides/METABOLISM Pepstatins/PHARMACOLOGY Protein Folding
Protein Structure, Secondary Substrate Specificity JOURNAL ARTICLE
SOURCE: National Library of Medicine. NOTICE: This material may be
protected by Copyright Law (Title 17, U.S.Code).