Thermo Scientific Maxima H Minus Reverse Transcriptase (RT) was developed through in vitro evolution of M-MuLV RT. The enzyme possesses an RNA-dependent and DNA-dependent polymerase activity but lacks RNase H activity due to mutation in RNase H domain of M-MuLV RT. The engineered enzyme features dramatically improved thermostability, 50X higher processivity, robustness, and increased synthesis rate compared to wild type M-MuLV RT.
The eliminated RNase H activity enables the enzyme to produce very long RNA transcripts up to 20 kb. Due to its high thermostability, the enzyme maintains full activity during the entire reverse transcription reaction and generates high yields of cDNA. The reaction temperature can be increased to 65°C for efficient transcription of RNA regions with a high secondary structure or to improve specificity using gene specific primers. The extremely high processivity of Maxima H Minus enzyme results in increased resistance to common reaction inhibitors, such as guanidine, formamide, and ethanol.