Close Genetic Linkage of the Determinants of the Ribitol and d -Arabitol Catabolic Pathways in Klebsiella aerogenes

Escherichia coli C strains can grow at the expense of' the two natural pentitols ribitol and D-arabitol, sugar alcohols previously thought not to be utilized by E. coli. E. coli strains K-12 and B cannot utilize either compound. The genetic loci responsible for pentitol catabolism in E. coli C. designated rtl and atl, are separate and closely linked. Each lies between metG and his and is highly co-transducible with metG and with a P2 prophage attachment site. rtl and atl readily can be transduced into E. coli K-12 or B strains, in which they integrate at, or very near, their E. coli C location. Transduction also can be used to insert rtl and atl into certain E. coli K-12 F' plasmids. No recombination between E. coli C strains and either K-12 or B strains occurs within the rtl-atl genetic region after interstrain conjugations or transductions. No cryptic rtl or atl genes in K-12 or B strains can be detected by complementation, recombination, or mutagenesis. These results are consistent with the view that the rtl-atl portion of the E. coli C chromosome has no counterpart in E. coli K-12 or B and may have been obtained from an extrageneric source. Detailed biochemical and genetic comparisons of' pentitol utilization in E. coli and Klebsiella aerogenes are in progress. The ability to catabolize xylitol is conferred upon E. coli C strains by a mutation at or adjacent to the rtl locus, whereas in E. coli K-12 or B strains harboring rtl an additional mutation at a separate locus is required for xvlitol utilization.Ribitol, D-arabitol, L-arabitol. and xylitol are the four structurallv possible C5 polyol epimers. Ribitol and D-arabitol, the two that are found commonly in nature (6). can serve as the sole carbon and energy sources for natural strains of Aerobacter (59), Klebsiella (12, 13), Pseudomonas (50), Azotobacter (39), and yeast (1). Their metabolism, involving separate and inducible pathwavs, has been studied in considerable detail in A. aerogenes (2, 42. 55) and in K. aerogenes (12)(13)(14).

Section: Resultssupporting

confidence: 59%

“…Their metabolism, involving separate and inducible pathwavs, has been studied in considerable detail in A. aerogenes (2, 42. 55) and in K. aerogenes (12)(13)(14).…”

mentioning

confidence: 99%

Genes for ribitol and D-arabitol catabolism in Escherichia coli: their loci in C strains and absence in K-12 and B strains

Reiner¹

1975

“…This result raised the possibility that all the genes for pentitol metabolism are clustered in one region of the chromosome. This conclusion has been confirmed and considerably extended (7) by studies with K. aerogenes phage PW52 which show that the structural and regulatory genes for the ribitol and D-arabitol pathways are closely linked.…”

Section: Resultsmentioning

confidence: 57%

“…Penicillin selections (8) were performed on mutagenized cells which had been starved in M9 medium for 30 min. The compound against which selection a Genetic nomenclature for pentitol utilization markers follow that previously proposed (7). The mutation to ribitol dehydrogenase constitutivity carried by K. aerogenes strain 1A has been arbitrarily assigned as rbtC; we have no evidence to distinguish it from rbtB (7).…”

mentioning

confidence: 92%

Construction of intergeneric hybrids using bacteriophage P1CM: transfer of the Klebsiella aerogenes ribitol dehydrogenase gene to Escherichia coli

Rigby¹,

Gething²,

Hartley³

1976

Study of many of the interesting properties of Klebsiella aerogenes is limited by the lack of a well-characterized genetic system for this organism. Our investigations of the evolution of the enzyme ribitol dehydrogenasel?EC -1.1.1.56) in K. aerogenes would be greatly facilitated by the availability of such a system, and we here report two approaches to developing one. We have isolated mutants sensitive to the coliphage P1, which will efficiently transduce genetic markers between such sensitive strains and which will thus make detailed mapping studies possible. Derivatives of K. aerogenes lysogenic for P1 can be readily isolated by using the specialized transducing particle PlCMclrlOO. Bacteria lysogenic for this phage are chloramphenicol resistant and temperature sensitive. Phage particles produced by temperature induction of such lysogens can be used to transfer K. aerogenes genes to the natural host of P1 phage, Escherichia coli. We have used this method to prepare derivatives of E. coli K-12 carrying the K. aerogenes genes conferring the ability to metabolize the pentitols ribitol and D-arabitol. We have shown that these E. coli-K. aerogenes hybrids synthesize a ribitol dehydrogenase with the properties of the K. aerogenes enzyme and have mapped the position of the transferred gene on the E. coli chromosome. The ramifications of this methodology are discussed.

“…There are other divergent Klebsiella operons. One example is the organization of the pentitol operons (4,13). The rbt operon that encodes ribitol dehydrogenase and Dribulokinase is positioned head to head with the dal operon that encodes D-arabitol dehydrogenase and D-xylulokinase.…”

Section: For Further Explanation See the Legends Tomentioning

confidence: 99%

Regulatory region of the divergent Klebsiella pneumoniae lac operon

Buvinger¹,

Riley²

1985

The chromosomal DNA that lies between the lad and lacZ genes of Klebsiella pneumoniae constitutes a 196-base pair intercistronic region that contains regulatory sequences for both genes. The probable locations of specific regulatory elements for both lacI and lacZ genes were determined by analogy with the corresponding Escherichia coli sequences. A recombinational event in ancestral DNA evidently has inverted the transcriptional direction of lac in K. pneumoniae relative to the transcriptional direction of lacI in E. coli. One end of the inversion was located within a 19-base pair sequence in the K. pneumoniae regulatory region. Sequences partially homologous to these 19 base pairs were found In two locations on either side of the E. coli lacI gene. The nucleotide sequence of the lac regulatory region in K. pneumoniae exhibits more than one possibility for folded tertiary structures. The spatial relationships of transcriptional binding sites differ in two possible structures. Associations of regulatQry and transcriptional proteins with the DNA might affect conformation of the regulatory sequences and, as a consequence, transcription of the lac genes.Most of the chromosomal lac operon of Klebsiella pneumoniae was cloned as a 4.8-kilobase HindIII fragment in the vector pBR322 (11). In the accompanying paper we describe nucleotide sequence determination of a functional lacI gene, the complete lacZ gene, and part of the lacY gene (2). The transcriptional directions of these three genes were determined by locating regions of hotollgy to the corresponding Escherichia coli lac genes. The location and orientation of the genes showed that the K. pneumoniae lac genes are organized in a divergent fashion (2). The lacI gene lies head to head with the lacZ gene and is transcribed from the opposite strand of the DNA in relation to the lacZ and lacY genes. The sequence of the intercistronic region that lies between the lacI and lacZ genes was also determined and is reported here. This region consists of 196 base pairs (bp) that contain the information needed to initiate expression of both the lacI gene and the lacZ gene. This intercistronic sequence was analyzed in relation to E. coli lac operon regulatory sequences and in terms of evolutionary relationships. Potential alternate conformational forms of the DNA were explored and are discussed below. MATERIALS AND METHODSThe procedures used for isolating plasmid DNA, cloning the PstI fragments, preparing sets ofdeletion derivatives, and determining nucleotide sequences of both strands of the DNA, as well as the sequence-managing programs and the origin of the file containing the nucleotide sequence of the E. coli lac operon, are described in the accompanying paper (2). To examine the potential for folded structure and to calculate free energy contents, the algorithm for folding RNA of Zuker and Steigler (17) was used as adapted by Jacobson et al. (8) and was run on a Univac model 1100 computer. RESULTSThe intercistronic region that lies between the coding regions of the K. pneumo...