Structure of the unbound form of HIV-1 subtype A protease: comparison with unbound forms of proteases from other HIV subtypes.
The crystal structure of the unbound form of HIV-1 subtype A protease (PR) has been determined to 1.7 A resolution and refined as a homodimer in the hexagonal space group P6(1) to an R(cryst) of 20.5%. The structure is similar in overall shape and fold to the previously determined subtype B, C and F PRs. The major differences lie in the conformation of the flap region. The flaps in the crystal structures of the unbound subtype B and C PRs, which were crystallized in tetragonal space groups, are either semi-open or wide open. In the present structure of subtype A PR the flaps are found in the closed position, a conformation that would be more anticipated in the structure of HIV protease complexed with an inhibitor. The amino-acid differences between the subtypes and their respective crystal space groups are discussed in terms of the differences in the flap conformations.
Robbins
Arthur H
AH
Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL 32610, USA.
Coman
Roxana M
RM
Bracho-Sanchez
Edith
E
Fernandez
Marty A
MA
Gilliland
C Taylor
CT
Li
Mi
M
Agbandje-McKenna
Mavis
M
Wlodawer
Alexander
A
Dunn
Ben M
BM
McKenna
Robert
R
D000595:Amino Acid Sequence; D018360:Crystallography, X-Ray; D016333:HIV Protease / Q000737:chemistry* / Q000378:metabolism; D015497:HIV-1 / Q000201:enzymology*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017510:Protein Folding; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment
D016333:HIV Protease