Characterization of reverse transcriptase from feline immunodeficiency virus.

Area of Science:

• Virology
• Molecular Biology
• Biochemistry

Background:

• Feline immunodeficiency virus (FIV) is a lentivirus that infects cats.
• Reverse transcriptase is a key enzyme in the replication cycle of retroviruses, including FIV and HIV.
• Understanding viral enzyme structure and function is crucial for developing antiviral therapies.

Purpose of the Study:

• To purify and characterize the reverse transcriptase enzyme from FIV.
• To compare the properties of FIV reverse transcriptase with that of human immunodeficiency virus type 1 (HIV) reverse transcriptase.

Main Methods:

• Purification of FIV reverse transcriptase using DEAE-cellulose and phosphocellulose chromatography.
• Analysis of enzyme molecular weight (Mr) and polypeptide composition.
• Peptide mapping to assess primary sequence differences.
• Comparison of template specificity and Mg2+ requirements.

Main Results:

• FIV reverse transcriptase was purified as a single protein of Mr 67,000, with a Mr 54,000 fragment observed under non-optimized conditions.
• HIV reverse transcriptase consists of a Mr 66,000 polypeptide, with a Mr 51,000 fragment under similar conditions.
• FIV and HIV reverse transcriptases exhibited similar template specificity and Mg2+ requirements.
• Peptide mapping revealed substantial differences in the primary sequence of FIV and HIV reverse transcriptases.

Conclusions:

• FIV reverse transcriptase is biochemically similar to HIV reverse transcriptase in enzymatic activity.
• Despite functional similarities, significant primary sequence divergence exists between FIV and HIV reverse transcriptases.
• These findings contribute to the understanding of lentiviral enzyme evolution and diversity.