w ~ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . eptidyl-prolyl cis-trans isomeras not essentiai Ruben G. Kok, Vincent M. Christoffel Department of Microbiology, E.C. Slater Institute, BioCentrumAmst~ Received 24 February ] tact 3wnstream of the Acinetobacter calcoaceticus estA gene, encc i may encode a protein with a mass of 20.4 kDa. This pr~ dyl-prolyl cis-trans isomerases (PPIases) of the cyclophilin su A putative signal sequence suggests that the product of the A cription of the gene is initiated from a promoter, just upstre on mutants display no apparent mutant phenotype, suggests ats, to our knowledge, are the first prokaryotic PPIase mutant 9rds: Peptidyl-prolyl cis-trans isomerase; PPIase; Rotamase; Esteras~ ene, encoding a cell-bound esterase, an o 1 ~rotein shows extensive similarit,. sub-class, especially to the peripl~ Acinetobacter gene, we termed t 9stream of the rotA off. The obser~ that this PPIase is not essenti~ mutants reported. Esterase; Mutant; Sequence isomerase (PPIase) was first Since these initial J y in 1984 [1] and found to prokaryotic organisms ion of a proline peptide (Xaa- PPIases have been idenl ity) in synthetic peptide-p- sequenced. Sequence co dently and simultaneously, a revealed strong similarit ~or binding of the immuno- and within the FKBP : n A (CsA) was reported [2], sub-classes of protein e ~hocyte activation. Upon dis- very little homology bee philin were the same proteins [7]. Here, based on the is new class of enzymes in- the identification of a lly after the identification of cyclophilin sub-class fr~ 506-binding proteins; FKBP), addition, mutant strains 'ly T-cell activation events, as fled, that lack the PPIas~ Plasmid pAKA24-5, (kbp) insert of chromos BD413, encodes a cell 2458 bp PvulI/BclI fragment of A. reported the nucleotid esterase and the PPIase, will appear PvulI/HpaI fragment, c Jucleotide Sequence Databases under In order to identify pos which peptidyl-r coli. A Transcri deleti~ mutants Keywords: Peptidyl-prolyl cis-trans lsomera discovered in porcine kidne~ catalyze cis-trans isomerization Pro) bond (rotamase activit' nitroanilids in vitro. Independently target-protein (cyclophilin) for suppressive agent cyclosporin that was involved in T-lymphoc~ covery that PPIase and cyclo t [3,4] scientific interest in this creased dramatically, especially another group of proteins (FK506-bin that were also involved in earl~ a distinct sub-class of PPIases [5,6]. eThe nucleotide sequence of the 2458 calcoaceticus BD413, encoding the in the EMBL, GenBank and DDBJ Nucleotide accession number X74839. * Corresponding author. Fax: +31 20 5 @horus.sara.nl. 1 Present address: Centre for Plant Breedi c~roh (F~DDF~_T~T F~ D~otht,c 1 F~ ~"TN/~ A A Biochimica et BiophysicaActa 1219 (1994 bacter calcoaceticus merase of tt essential for g Christoffels, Ben' BioCentrum Amsterdam, Nieu 1994; revise~ erase bindin et Bioj encodes a peril: )philin sub-class , Klaas J. Hellingwer t 127, 1018 WSAmsterdam, The? pen reading frame (off y to both prokaryotic ~lasmic rotamase (RotA) rotA, is located outside observation that two A. cai essential for growth of the reports, in both e cyclophilin-type an identified, and their gen comparisons between imilarity within the cyclop sub-class. However exhibit similar func between these two gro~ nucleotide sequenc~ gene encoding a ] from A. calcoaceticz from this organisn PPIase gene. which carries a 2.4 omosomal DNA of A. , cell-bound esterase. P lcleotide sequence of t encoding the estera~, ~ossible orfs downstre~ clI fragment of pAKA24- nd M13mpl9. The nuclec ~y the dideoxy-chain termi ase version 2.0 (U.S. Bio miversal primers or custo