home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
The Pier Shareware 6
/
The_Pier_Shareware_Number_6_(The_Pier_Exchange)_(1995).iso
/
026
/
med9410a.zip
/
M94A0153.TXT
< prev
next >
Wrap
Text File
|
1994-10-01
|
3KB
|
47 lines
Document 0153
DOCN M94A0153
TI The HIV-1 protease as enzyme and substrate: mutagenesis of autolysis
sites and generation of a stable mutant with retained kinetic
properties.
DT 9412
AU Mildner AM; Rothrock DJ; Leone JW; Bannow CA; Lull JM; Reardon IM;
Sarcich JL; Howe WJ; Tomich CS; Smith CW; et al; Biochemistry Unit,
Upjohn Laboratories, Kalamazoo, Michigan; 49001.
SO Biochemistry. 1994 Aug 16;33(32):9405-13. Unique Identifier : AIDSLINE
MED/94347706
AB Site-directed mutagenesis of autolysis sites in the human
immunodeficiency virus type 1 (HIV-1) protease was applied in an
analysis of enzyme specificity; the protease served, therefore, as both
enzyme and substrate in this study. Inspection of natural substrates of
all retroviral proteases revealed the absence of beta-branched amino
acids at the P1 site and of Lys anywhere from P2 through P2'.
Accordingly, several mutants of the HIV-1 protease were engineered in
which these excluded amino acids were substituted at their respective P
positions at the three major sites of autolysis in the wild-type
protease (Leu5-Trp6, Leu33-Glu34, and Leu63-Ile64), and the mutant
enzymes were evaluated in terms of their resistance to autodegradation.
All of the mutant HIV-1 proteases, expressed as inclusion bodies in
Escherichia coli, were enzymatically active after refolding, and all
showed greatly diminished rates of cleavage at the altered autolysis
sites. Some, however, were not viable enzymatically because of poor
physical characteristics. This was the case for mutants having Lys
replacements of Glu residues at P2' and for another in which all three
P1 leucines were replaced by Ile. However, one of the mutant proteases,
Q7K/L33I/L63I, was highly resistant to autolysis, while retaining the
physical properties, specificity, and susceptibility to inhibition of
the wild-type enzyme. Q7K/L33I/L63I should find useful application as a
stable surrogate of the HIV-1 protease. Overall, our results can be
interpreted relative to a model in which the active HIV-1 protease dimer
is in equilibrium with monomeric, disordered species which serve as the
substrates for autolysis.
DE Amino Acid Sequence Comparative Study HIV
Protease/GENETICS/*METABOLISM HIV Protease Inhibitors/PHARMACOLOGY
HIV-1/*ENZYMOLOGY Models, Molecular Molecular Sequence Data
Mutagenesis, Site-Directed Oligopeptides/METABOLISM Protein
Conformation *Protein Processing, Post-Translational
Structure-Activity Relationship Substrate Specificity JOURNAL ARTICLE
SOURCE: National Library of Medicine. NOTICE: This material may be
protected by Copyright Law (Title 17, U.S.Code).