Closing of the fingers domain generates motor forces in the HIV reverse transcriptase.
J Biol Chem
; 279(52): 54529-32, 2004 Dec 24.
Article
em En
| MEDLINE
| ID: mdl-15385563
ABSTRACT
Using the force sensor of an atomic force microscope, motor forces of the human immunodeficiency virus-1 reverse transcriptase were measured during active replication of a short DNA transcript. At low load forces the polymerase is mechanically slowed, whereas at high force (approximately 15 piconewton) it stalls. From recordings of estimated polymerase turnover velocity versus load force, an approximate force-velocity curve has been constructed. The shape of the curve suggests that load force strongly inhibits the rate-limiting step of the polymerase turnover cycle and that the combined effect of load on all steps involves an effective motion of about 1.6 nm. Earlier results from pre-steady-state kinetics experiments have identified the rate-limiting step as the closing of the fingers domain to form a tight catalytic complex. Together these findings indicate that the closing of the fingers domain is a major force-generating step for human immunodeficiency virus reverse transcriptase and, by extension, for all DNA polymerase machines.
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Base de dados:
MEDLINE
Assunto principal:
Transcriptase Reversa do HIV
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
J Biol Chem
Ano de publicação:
2004
Tipo de documento:
Article
País de afiliação:
Estados Unidos