       Document 0994
 DOCN  M9540994
 TI    Effect of point mutations on the kinetics and the inhibition of human
       immunodeficiency virus type 1 protease: relationship to drug resistance.
 DT    9504
 AU    Lin Y; Lin X; Hong L; Foundling S; Heinrikson RL; Thaisrivongs S;
       Leelamanit W; Raterman D; Shah M; Dunn BM; et al; Protein Studies
       Program, Oklahoma Medical Research Foundation,; Oklahoma City.
 SO    Biochemistry. 1995 Jan 31;34(4):1143-52. Unique Identifier : AIDSLINE
       MED/95127685
 AB    Mutations of human immunodeficiency virus type 1 (HIV-1) protease at
       four positions, Val82, Asp30, Gly48, and Lys45 were analyzed for the
       resulting effects on kinetics and inhibition. In these mutants, Val82
       was substituted separately by Asn, Glu, Ala, Ser, Asp, and Gln; Asp30
       was individually substituted by Phe or Trp; Gly48 by His, Asp, and Tyr,
       respectively; and Lys45 by Glu. By examination of the inhibition of a
       single inhibitor, the differences in Ki values between the native and
       mutant enzymes can range from very large to insignificant even for the
       mutants with substitutions at the same position. By examination of a
       single mutant enzyme, the same broad range of Ki changes was observed
       for a group of inhibitors: Thus, how much the inhibition changes from
       the wild-type enzyme to a mutant is dependent on both the mutation and
       the inhibitor. The examination of Ki changes of inhibitors with closely
       related structures binding to Val82 mutants also reveals that the change
       of inhibition involves subsites in which Val82 is not in direct contact,
       indicating a considerable flexibility of the conformation of HIV
       protease. For the catalytic activities of the mutants, the kcat and Km
       values of many Val82 mutants and a Lys45 mutant are comparable to the
       native enzyme. Surprisingly, Gly48 mutations produce enzymes with
       catalytic efficiency superior to that of the wild-type enzyme by as much
       as 10-fold. Modeling of the structure of the mutants suggests that the
       high catalytic efficiency of some substrates is related to an increase
       of rigidity of the flap region of the mutants. The examination of the
       relative changes of inhibition and catalysis of mutants suggests that
       some of the Val82 and Gly48 mutants are potential resistance mutants.
       However, the resistance is specific with respect to individual
       inhibitors.
 DE    Amino Acid Sequence  Base Sequence  Catalysis  DNA Primers/CHEMISTRY
       Hydrogen-Ion Concentration  HIV Protease/*CHEMISTRY/ULTRASTRUCTURE  HIV
       Protease Inhibitors/*CHEMISTRY  Kinetics  Models, Molecular  Molecular
       Sequence Data  Motion  Mutagenesis, Site-Directed  Peptides/METABOLISM
       Point Mutation  Protein Structure, Tertiary  Structure-Activity
       Relationship  Substrate Specificity  Support, U.S. Gov't, P.H.S.
       JOURNAL ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).

