Protein splicing of an intein from the extreme halophile Halobacterium salinarum (768.9)

Abstract

Protein splicing is the self‐catalyzed excision of an intervening polypeptide (intein) from flanking polypeptides (exteins), concomitant with the ligation of the extein. An intein in the archaebacterium Halobacterium salinarum (Hsa) interrupts the DNA Polymerase II. We have observed that the Hsa intein splices poorly in Escherichia coli cells, unlike two highly related inteins found in Pyrococcus abyssi and Methanoculleus marisnigri, which are not halophilic. To test if splicing activity depends on salinity, we altered the expression conditions by varying the salinity of the growth media and of in vitro activity assays. Future experiments will involve in vivo techniques by over‐expressing the intein and the flanking exteins into Hsa, and by using antibodies to detect possible splicing of the native protein. Grant Funding Source: Supported by the National Science Foundation under grant MCB‐1244089 and by the Dreyfus Foundation