Engineering split intein DnaE from Nostoc punctiforme for rapid protein purification

作者：Ramirez Miguel; Valdes Najla; Guan Dongli; Chen Zhilei^*

来源：Protein Engineering Design and Selection, 2013, 26(3): 215-223.

DOI：10.1093/protein/gzs097

• C-cleavage
• protein purification
• rational design
• redox trap
• split intein

We report the engineering of a DnaE intein able to catalyze rapid C-terminal cleavage in the absence of N-terminal cleavage. A single mutation in DnaE intein from Nostoc punctiforme PCC73102 (NpuDnaE), Asp118Gly, was introduced based on sequence alignment with a previously engineered C-terminal cleaving intein mini-MtuRecA. This mutation was able to both suppress N-terminal cleavage and significantly elevate C-terminal cleavage efficiency. Molecular modeling suggests that in NpuDnaE Asp118 forms a hydrogen bond with the penultimate Asn, preventing its spontaneous cyclization prior to N-terminal cleavage. Mutation of Asp118 to Gly essentially abolishes this restriction leading to subsequent C-terminal cleavage in the absence of N-terminal cleavage. The Gly118 NpuDnaE mutant exhibits rapid thio-dependent C-terminal cleavage kinetics with 80 completion within 3 h at room temperature. We used this newly engineered intein to develop both column-free and chromatography-based protein purification methods utilizing the elastin-like-polypeptide and chitin-binding protein as removable purification tags, respectively. We demonstrate rapid target protein purification to electrophoretic purity at yields up to 84 mg per liter of Escherichia coli culture.

• 出版日期2013-3