Lysine-329 of murine leukemia virus reverse transcriptase: possible involvement in the template-primer binding...

Area of Science:

• Biochemistry
• Molecular Biology
• Enzymology

Background:

• Murine leukemia virus reverse transcriptase (MuLV RT) is a crucial enzyme in retroviral replication.
• Understanding the mechanisms of MuLV RT inhibition is vital for developing antiviral therapies.

Purpose of the Study:

• To investigate the inhibitory mechanism of 4-(oxoacetyl)-phenoxyacetic acid (OAPA) on MuLV RT.
• To identify the specific site of OAPA action on the MuLV RT enzyme.

Main Methods:

• Enzyme activity assays (DNA polymerase and RNase-H) were performed.
• Binding stoichiometry of OAPA to MuLV RT was determined.
• Peptide mapping using tryptic digestion and C-18 reverse-phase HPLC was employed.
• Amino acid composition and sequence analysis of modified peptides were conducted.

Main Results:

• OAPA treatment resulted in loss of DNA polymerase and template-primer binding activity, but not RNase-H activity.
• Approximately 3 mol of OAPA bound per mole of enzyme for complete inhibition.
• In the presence of template-primer, 2 mol of OAPA bound, and polymerase activity was retained.
• A unique tryptic peptide (residues 312-342) was identified upon OAPA treatment.
• Lysine-329 was identified as the specific target residue for OAPA action.

Conclusions:

• OAPA selectively inhibits MuLV RT DNA polymerase activity by targeting Lys-329.
• The binding of template-primer influences OAPA interaction and its inhibitory effect.
• This study elucidates a specific molecular mechanism for MuLV RT inhibition.