English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Thymidine analog mutations (TAMs) in human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) confer resistance to zidovudine (AZT) by increasing the rate of ATP-dependent phosphorolysis of the terminal nucleotide monophosphate (primer unblocking). By contrast, the L74V mutation, which confers resistance to didanosine, sensitizes HIV-1 to AZT and partially restores AZT susceptibility when present together with one or more TAMs. To compare rates of primer unblocking in RTs carrying different clusters of TAMs and to explore the biochemical mechanism by which L74V affects AZT susceptibility, ATP-mediated rescue of AZT-blocked DNA synthesis was assayed using a series of purified recombinant RTs. Rates of primer unblocking were higher in the 67N/70R/219Q RT than in the 41L/210W/215Y enzyme and were similar to rates observed with an RT carrying six TAMs (41L/67N/70R/210W/215Y/219Q). The presence of 74V in an otherwise wild-type RT reduced the rate of primer unblocking to a degree similar to that observed with the M184V mutation for lamivudine resistance, which also sensitizes HIV-1 to AZT. Introduction of 74V into RTs carrying TAMs partially counteracted the effect of TAMs on the rate of primer unblocking. The effect of 74V was less marked than that of the 184V mutation in the 67N/70R/219Q and 41L/210W/215Y RTs but similar in the RT carrying six TAMs. These results demonstrate that L74V enhances AZT susceptibility by reducing the extent of its removal by ATP-dependent phosphorolysis and provides further evidence for a common mechanism by which mutations conferring resistance to didanosine and lamivudine sensitize HIV-1 to AZT.

antimicrobial agents and chemotherapy

The L74V Mutation in Human Immunodeficiency Virus Type 1 Reverse Transcriptase Counteracts Enhanced Excision of Zidovudine Monophosphate Associated with Thymidine Analog Resistance Mutations