IN-VIVO PROTEIN-FOLDING - SUPPRESSOR ANALYSIS OF MUTATIONS IN THE GROES COCHAPERONE GENE OF ESCHERICHIA-COLI

Our previous work has shown that the Escherichia coli groES14 and groE S15 mutations result in reduced GroE chaperone machine function. By se lecting for restoration of the ability of those mutant groES alleles t o suppress the thermosensitivity of bacteria bearing the dnaA46 mutati on, we isolated a number of intra- and extragenic suppressors that inc rease in vivo GroE chaperone function. One of the intragenic suppresso rs has been mapped to a segment that codes for the GroES mobile loop, previously shown to be indispensable for proper GroES/GroEL interactio n, Two extragenic suppressors have been mapped to a groEL segment, pre viously identified by mutational analysis as coding for an important f unctional region of the GroEL protein. Our results should contribute t o our eventual understanding of the structure-function relationships o f the universally conserved GroE chaperone machine.