Open AccessStructure of the unbound form of HIV‐1 subtype A protease: comparison with unbound forms of proteases from other HIV subtypes
Author(s) -
Robbins Arthur H.,
Coman Roxana M.,
BrachoSanchez Edith,
Fernandez Marty A.,
Gilliland C. Taylor,
Li Mi,
AgbandjeMcKenna Mavis,
Wlodawer Alexander,
Dunn Ben M.,
McKenna Robert
Publication year - 2010
Publication title -
acta crystallographica section d
Language(s) - English
Resource type - Journals
ISSN - 1399-0047
DOI - 10.1107/s0907444909054298
Subject(s) - proteases , protease , tetragonal crystal system , crystal structure , hiv 1 protease , human immunodeficiency virus (hiv) , chemistry , crystallography , stereochemistry , biology , virology , enzyme , biochemistry
The crystal structure of the unbound form of HIV‐1 subtype A protease (PR) has been determined to 1.7 Å resolution and refined as a homodimer in the hexagonal space group P 6 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.