Preceding hydrophobic and beta-branched amino acids attenuate splicing by the CnePRP8 intein.
As the Cne PRP8 intein is active and exists in an essential gene of an important fungal pathogen, inhibitors of splicing and assays for intein activity are of interest. The self-splicing activity of Cne PRP8, the intein from the Prp8 gene of Cryptococcus neoformans, was assessed in different heterologous fusion proteins expressed in Escherichia coli. Placement of a putatively inactive variant of the intein adjacent to the alpha-complementation peptide abolished the peptide's ability to restore beta-galactosidase activity, while an active variant allowed complementation. This alpha-complementation peptide therefore provides a facile assay of splicing which can be used to test potential inhibitors. When placed between two heterologous protein domains, splicing was impaired by a beta-branched amino acid immediately preceding the intein, while splicing occurred only with a hydroxyl or thiol immediately following the intein. Both these assays sensitively report impairment of splicing and provide information on how context constrains the splicing ability of Cne PRP8.
Pearl
Esther J
EJ
Department of Biochemistry, University of Otago, PO Box 56, Dunedin, New Zealand.
Bokor
Annika A M
AA
Butler
Margi I
MI
Poulter
Russell T M
RT
Wilbanks
Sigurd M
SM
D000596:Amino Acids / Q000235:genetics / Q000378:metabolism*; D001681:Biological Assay; D003455:Cryptococcus neoformans / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D005816:Genetic Complementation Test; D057927:Hydrophobic and Hydrophilic Interactions; D047668:Inteins / Q000502:physiology*; D019154:Protein Splicing / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
D000596:Amino Acids; D005656:Fungal Proteins; D011993:Recombinant Fusion Proteins; D001616:beta-Galactosidase