Abstract: Described are protein constructs of Moloney murine leukemia virus reverse transcriptase (MMLV-RT). In one embodiment the protein construct comprises a Moloney murine leukemia virus reverse transcriptase (MMLV) mature protein sequence; and an expression enhancement sequence at the N-terminus of said MMLV mature protein sequence. The expression enhancement sequence is devised for providing heterologous expression of the protein construct in bacterial cells in absence of chaperone co-expression and/or to provide high-level of expression of the MMLV. In another embodiment the protein construct further comprises a tag/linker combo at the N-terminus of the expression enhancement sequence for assisting in purification of the protein construct. Also described are isolated nucleic acid molecules, vectors and methods for expressing the protein construct in cells. Advantageously these allow large-scale expression of MMLV-RT from cultures of E. coli cells and simplify protocols for purification of MMLV-RT at high purity.