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Pasricha R, Chandolia A, Ponnan P, Saini NK, Sharma S, Chopra M, Basil MV, Brahmachari V, Bose M. Single nucleotide polymorphism in the genes of mce1 and mce4 operons of Mycobacterium tuberculosis: analysis of clinical isolates and standard reference strains. BMC Microbiol 2011; 11:41. [PMID: 21345183 PMCID: PMC3050694 DOI: 10.1186/1471-2180-11-41] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Accepted: 02/23/2011] [Indexed: 12/02/2022] Open
Abstract
Background The presence of four mammalian cell entry (mce) operons in Mycobacterium tuberculosis suggests the essentiality of the functions of the genes in these operons. The differential expression of the four mce operons in different phases of in vitro growth and in infected animals reported earlier from our laboratory further justifies the apparent redundancy for these genes in the genome. Here we investigate the extent of polymorphism in eight genes in the mce1 and mce4 operons of M. tuberculosis from four standard reference strains (H37Rv, H37Ra, LVS (Low Virulent Strain) and BCG) and 112 clinical isolates varying in their drug susceptibility profile, analysed by direct sequencing and Sequenom MassARRAY platform. Results We discovered 20 single nucleotide polymorphisms (SNPs) in the two operons. The comparative analysis of the genes of mce1 and mce4 operons revealed that yrbE1A [Rv0167] was most polymorphic in mce1 operon while yrbE4A [Rv3501c] and lprN [Rv3495c] had the highest number of SNPs in the mce4 operon. Of 20 SNPs, 12 were found to be nonsynonymous and were further analysed for their pathological relevance to M. tuberculosis using web servers PolyPhen and PMut, which predicted five deleterious nonsynonymous SNPs. A mutation from proline to serine at position 359 of the native Mce1A protein was most deleterious as predicted by both PolyPhen and PMut servers. Energy minimization of the structure of native Mce1A protein and mutated protein was performed using InsightII. The mutated Mce1A protein showed structural changes that could account for the effects of this mutation. Conclusions Our results show that SNPs in the coding sequences of mce1 and mce4 operons in clinical isolates can be significantly high. Moreover, mce4 operon is significantly more polymorphic than mce1 operon (p < 0.001). However, the frequency of nonsynonymous substitutions is higher in mce1 operon and synonymous substitutions are more in mce4 operon. In silico modeling predict that nonsynonymous SNP at mce1A [Rv0169], a virulence gene could play a pivotal role in causing functional changes in M. tuberculosis that may reflect upon the biology of the bacteria.
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Affiliation(s)
- Rashmi Pasricha
- Department of Microbiology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi-110007, India
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2
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Droniuk R, Wong PT, Wisse G, Macleod RA. Variation in Quantitative Requirements for Na for Transport of Metabolizable Compounds by the Marine Bacteria Alteromonas haloplanktis 214 and Vibrio fischeri. Appl Environ Microbiol 2010; 53:1487-95. [PMID: 16347378 PMCID: PMC203897 DOI: 10.1128/aem.53.7.1487-1495.1987] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The rates of uptake by Alteromonas haloplanktis of 19 metabolizable compounds and by V. fischeri of 16 of 17 metabolizable compounds were negligible in the absence of added alkali-metal cations but rapid in the presence of Na. Only d-glucose uptake by V. fischeri occurred at a reasonable rate in the absence of alkali-metal cations, although the rate was further increased by added Na, K, or Li. Quantitative requirements for Na for the uptake of 11 metabolites by A. haloplanktis and of 6 metabolites by V. fischeri and the characteristics of the Na response at constant osmotic pressure varied with each metabolite and were different from the Na effects on the energy sources used. Li stimulated transport of some metabolites in the presence of suboptimal Na concentrations and for a few replaced Na for transport but functioned less effectively. K had a small capacity to stimulate lysine transport. The rate of transport of most of the compounds increased to a maximum at 50 to 300 mM Na, depending on the metabolite, and then decreased as the Na concentration was further increased. For a few metabolites, the rate of transport continued to increase in a biphasic manner as the Na concentration was increased to 500 mM. Concentrations of choline chloride equimolar to inhibitory concentrations of NaCl were either not inhibitory or appreciably less inhibitory than those of NaCl. All metabolites examined accumulated inside the cells against a gradient of unchanged metabolite in the presence of Na, even though some were very rapidly metabolized. The transport of l-alanine, succinate, and d-galactose into A. haloplanktis and of l-alanine and succinate into V. fischeri was inhibited essentially completely by the uncoupler 3,5,3',4'-tetrachlorosalicylanilide. Glucose uptake by V. fischeri was inhibited partially by 3,5,3',4'-tetrachlorosalicylanilide and also by arsenate and iodoacetate.
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Affiliation(s)
- R Droniuk
- Department of Microbiology, Macdonald College of McGill University, Ste. Anne de Bellevue, Quebec, Canada H9X ICO
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3
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Ding PZ, Botfield MC, Wilson TH. Sugar recognition mutants of the melibiose carrier of Escherichia coli: possible structural information concerning the arrangement of membrane-bound helices and sugar/cation recognition site. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1509:123-30. [PMID: 11118524 DOI: 10.1016/s0005-2736(00)00286-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Melibiose carrier mutants, isolated by growing cells on melibiose plus the non-metabolizable competitive inhibitor thiomethyl-beta-galactoside (TMG), were studied to determine sugar and cation recognition abnormalities. Most of the mutants show good transport of melibiose but have lost the recognition of TMG. In addition, most mutants show little or no transport of lactose. Cation recognition is also affected as all of these mutants have lost the ability to transport protons with melibiose. The amino acids causing these mutations were determined by sequencing the melB gene on the plasmid. The mutations were located on helices I, IV, VII, X and XI. We propose that these five helices are in proximity with each other and that they line the sugar/cation transport channel.
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Affiliation(s)
- P Z Ding
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
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4
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Cordat E, Leblanc G, Mus-Veteau I. Evidence for a role of helix IV in connecting cation- and sugar-binding sites of Escherichia coli melibiose permease. Biochemistry 2000; 39:4493-9. [PMID: 10757998 DOI: 10.1021/bi991852i] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To improve the structural organization model of melibiose permease, we assessed the individual contributions of the N-terminal tryptophans to the transporter fluorescence variations induced by the binding of cations and beta-configured sugars, by replacement of the six N-terminal tryptophans by phenylalanines and the study of the signal changes. Only two mutations, W116F located in helix IV and W128F located in the cytoplasmic loop 4-5, impair permease activity. The intrinsic fluorescence spectroscopy analysis of the other mutants suggests that W54, located in helix II, W116, and W128 are mostly responsible for the cation-induced fluorescence variations. These tryptophans, W116 and W128, would also be responsible for the beta-galactoside-induced fluorescence changes observed in the N-terminal domain of the transporter. The implication of W116 and W128 in both the cation- and beta-galactoside-induced fluorescence variations led us to investigate in detail the effects of their mutations on the functional properties of the permease. The results obtained suggest that the domains harboring the two tryptophans, or the residues themselves, play a critical role in the mechanism of Na(+)/sugar symport. Taken together, the results presented in this paper and previous results are consistent with a fundamental role of helix IV in connecting cation- and sugar-binding sites of the melibiose permease.
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Affiliation(s)
- E Cordat
- Laboratoire des Membranes Cellulaires (Bat. Jean Maetz), Université de Nice/Sophia-Antipolis, CNRS (ERS 1253), LRC-CEA 16V, 06238 Villefranche Sur Mer Cedex 1, France
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5
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Saier MH, Eng BH, Fard S, Garg J, Haggerty DA, Hutchinson WJ, Jack DL, Lai EC, Liu HJ, Nusinew DP, Omar AM, Pao SS, Paulsen IT, Quan JA, Sliwinski M, Tseng TT, Wachi S, Young GB. Phylogenetic characterization of novel transport protein families revealed by genome analyses. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1422:1-56. [PMID: 10082980 DOI: 10.1016/s0304-4157(98)00023-9] [Citation(s) in RCA: 171] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
As a result of recent genome sequencing projects as well as detailed biochemical, molecular genetic and physiological experimentation on representative transport proteins, we have come to realize that all organisms possess an extensive but limited array of transport protein types that allow the uptake of nutrients and excretion of toxic substances. These proteins fall into phylogenetic families that presumably reflect their evolutionary histories. Some of these families are restricted to a single phylogenetic group of organisms and may have arisen recently in evolutionary time while others are found ubiquitously and may be ancient. In this study we conduct systematic phylogenetic analyses of 26 families of transport systems that either had not been characterized previously or were in need of updating. Among the families analyzed are some that are bacterial-specific, others that are eukaryotic-specific, and others that are ubiquitous. They can function by either a channel-type or a carrier-type mechanism, and in the latter case, they are frequently energized by coupling solute transport to the flux of an ion down its electrochemical gradient. We tabulate the currently sequenced members of the 26 families analyzed, describe the properties of these families, and present partial multiple alignments, signature sequences and phylogenetic trees for them all.
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Affiliation(s)
- M H Saier
- Department of Biology, University of California at San Diego, La Jolla, CA 92093-0116, USA.
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6
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Okazaki N, Xu XJ, Shimamoto T, Kuroda M, Wilson TH, Tsuchiya T. Mutants of Citrobacter freundii that transport and utilize melibiose. J Bacteriol 1998; 180:3480-2. [PMID: 9642207 PMCID: PMC107309 DOI: 10.1128/jb.180.13.3480-3482.1998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
We have isolated mutants of Citrobacter freundii that can grow on melibiose. Inducible alpha-galactosidase activity and melibiose transport activity were detected in the mutant cells but not in the wild-type cells. We detected a DNA region which hybridized with melB (the gene for the melibiose transporter) DNA of Escherichia coli in the chromosomal DNA of wild-type C. freundii. Protons, but not sodium ions, were found to be the coupling cations for melibiose (and methyl-beta-D-thiogalactoside) transport in the mutant cells.
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Affiliation(s)
- N Okazaki
- Department of Microbiology, Faculty of Pharmaceutical Sciences, Okayama University, Japan
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7
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Weissborn AC, Botfield MC, Kuroda M, Tsuchiya T, Wilson TH. The construction of a cysteine-less melibiose carrier from E. coli. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1329:237-44. [PMID: 9371415 DOI: 10.1016/s0005-2736(97)00116-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The melibiose carrier of E. coli is a cation-sugar cotransport system. This membrane protein contains four cysteine residues and the transport function is inhibited by sulfhydryl reagents. In order to investigate the importance of the cysteines, we have constructed a set of four melibiose transporters each of which has one cysteine replaced with serine or valine. The sensitivity of this set of carriers to N-ethylmaleimide was tested and Cys364 was identified as the target of the reagent. In addition, we constructed a melibiose transporter in which all 4 cysteines were replaced with either serine (Cys110, Cys310, and Cys364) or valine (Cys235) and we found that, as expected, the resulting cysteine-less transporter was resistant to the action of N-ethylmaleimide. The cysteine-less melibiose carrier had no significant decrease in ability to accumulate melibiose with cotransported sodium ions or protons. Thus, none of the 4 cysteines are necessary for the function of the melibiose carrier.
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Affiliation(s)
- A C Weissborn
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
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8
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Okazaki N, Jue XX, Miyake H, Kuroda M, Shimamoto T, Tsuchiya T. Sequence of a melibiose transporter gene of Enterobacter cloacae. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1354:7-12. [PMID: 9375783 DOI: 10.1016/s0167-4781(97)00113-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We cloned a fragment of the chromosomal DNA of Enterobacter cloacae, which enabled a melibiose-negative Escherichia coli mutant lacking melB to grow on melibiose as the sole source of carbon. Transformed cells harboring the hybrid plasmid carrying the cloned DNA showed melibiose transport activity. The nucleotide sequence of the DNA region was determined. One complete open reading frame (ORF) and a part of another ORF were found in the region, and the amino acid sequences were deduced. The complete ORF was found to encode a melibiose transporter which consisted of 425 amino acid residues. Hydropathy analysis revealed that there are about 12 hydrophobic domains in this transporter. The incomplete ORF which exists in the upstream region of the transporter gene seemed to encode an alpha-galactosidase.
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Affiliation(s)
- N Okazaki
- Department of Microbiology, Faculty of Pharmaceutical Sciences, Okayama University, Tsushima, Japan
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9
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Okazaki N, Kuroda M, Shimamoto T, Shimamoto T, Tsuchiya T. Characteristics of the melibiose transporter and its primary structure in Enterobacter aerogenes. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1326:83-91. [PMID: 9188803 DOI: 10.1016/s0005-2736(97)00010-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Cells of Enterobacter aerogenes can grow on melibiose as a sole source of carbon. This suggests the presence of melibiose operon in this organism. We found that E. aerogenes cells possess both alpha-galactosidase activity and melibiose transport activity, which were induced by melibiose. Neither Na+ nor Li+ stimulated the melibiose transport. However, transport of methyl-beta-thiogalactoside (TMG) was stimulated by Li+ but not by Na+. These findings suggest that the major coupling cation for the melibiose transporter in E. aerogenes is H+. In fact, we observed H+ entry into cells caused by an influx of melibiose and some of its analogs. We cloned the melB gene which encodes the melibiose transporter, and sequenced it. Deduced amino acid sequence of the transporter revealed that the melibiose transporter consists of 471 amino acid residues and the molecular weight was calculated to be 52214 Da. The sequence showed high homology with the sequences of the melibiose transporters of Escherichia coli, Salmonella typhimurium and Klebsiella pneumoniae. Higher homology was found with the melibiose transporter of K. pneumoniae than with that of E. coli and S. typhimurium.
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Affiliation(s)
- N Okazaki
- Department of Microbiology, Faculty of Pharmaceutical Sciences, Okayama University, Tsushima, Japan
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10
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Young-Mog K, Tachibana Y, Shimamoto T, Shimamoto T, Tsuchiya T. Inhibition of melibiose transporter by amiloride in Escherichia coli. Biochem Biophys Res Commun 1997; 233:147-9. [PMID: 9144412 DOI: 10.1006/bbrc.1997.6420] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Amiloride inhibited the active transport of melibiose via the melibiose transporter in Escherichia coli. Since amiloride is known to inhibit the Na+/H+ antiporter which is essential for the establishment of an electrochemical potential of Na+ that is the driving force for melibiose transport, we tested the effect of amiloride on the activity of the melibiose transporter itself. Amiloride inhibited the melibiose counterflow. Also, inhibition of Na+ uptake induced by melibiose influx and some inhibition of H+ uptake induced by melibiose influx were observed. These results indicate that amiloride directly inhibits the melibiose transporter, perhaps by competing with Na+. It seems that the Na+ binding site and the H+ binding site in the melibiose transporter are somehow different from each other judging from the difference in the inhibition pattern of amiloride.
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Affiliation(s)
- K Young-Mog
- Department of Microbiology, Faculty of Pharmaceutical Sciences, Okayama University, Tsushima, Japan
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11
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Verkhovskaya ML, Verkhovsky MI, Wikström M. The respiration-driven active sodium transport system in E. coli does not function with lithium. FEBS Lett 1996; 388:217-8. [PMID: 8690090 DOI: 10.1016/0014-5793(96)00531-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Comparison of respiration-driven active transport of alkali cations from E. coli cells loaded with Na+ or Li+ showed that Li+ could not be expelled from the cells like Na+. K+ accumulation, which was fast in Na+-loaded cells, was strongly inhibited in Li+-loaded cells, despite high membrane potential and respiratory rate. When Li+-loaded cells were placed into medium containing Na+ instead of Li+, Li+/Na+ exchange took place initially, while K+ accumulation was delayed. Only after almost all inside Li+ was replaced by Na+ did active Na+ and K+ transport commence. These data confirm that it is a distinct active sodium transport system (AST) with Na+,K+/H+ antiporter activity, and not the Na+/H+ antiporters, that is responsible for active Na+ transport in E. coli [Verkhovskaya, M.L., Verkhovsky, M.I. and Wikstrom, M. (1996) Biochim. Biophys. Acta 1273, 207-216]. In contrast to the Na+/H+ antiporters, the AST system is inhibited by Li+.
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Affiliation(s)
- M L Verkhovskaya
- Helisinki Bioenegetics Group, Department of Medical Chemistry, Institute of Biomedical Sciences, University of Helsinki, Finland.
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12
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Reizer J, Reizer A, Saier MH. A functional superfamily of sodium/solute symporters. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1197:133-66. [PMID: 8031825 DOI: 10.1016/0304-4157(94)90003-5] [Citation(s) in RCA: 164] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Eleven families of sodium/solute symporters are defined based on their degrees of sequence similarities, and the protein members of these families are characterized in terms of their solute and cation specificities, their sizes, their topological features, their evolutionary relationships, and their relative degrees and regions of sequence conservation. In some cases, particularly where site-specific mutagenesis analyses have provided functional information about specific proteins, multiple alignments of members of the relevant families are presented, and the degrees of conservation of the mutated residues are evaluated. Signature sequences for several of the eleven families are presented to facilitate identification of new members of these families as they become sequenced. Phylogenetic tree construction reveals the evolutionary relationships between members of each family. One of these families is shown to belong to the previously defined major facilitator superfamily. The other ten families do not show sufficient sequence similarity with each other or with other identified transport protein families to establish homology between them. This study serves to clarify structural, functional and evolutionary relationships among eleven distinct families of functionally related transport proteins.
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Affiliation(s)
- J Reizer
- Department of Biology, University of California at San Diego, La Jolla 92093-0116
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13
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Padan E, Schuldiner S. Molecular physiology of Na+/H+ antiporters, key transporters in circulation of Na+ and H+ in cells. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1185:129-51. [PMID: 8167133 DOI: 10.1016/0005-2728(94)90204-6] [Citation(s) in RCA: 121] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- E Padan
- Department of Microbial and Molecular Ecology, Hebrew University of Jerusalem, Israel
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14
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Krämer R. Functional principles of solute transport systems: concepts and perspectives. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1185:1-34. [PMID: 7511415 DOI: 10.1016/0005-2728(94)90189-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- R Krämer
- Institut für Biotechnologie 1, Forschungszentrum Jülich, Germany
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15
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Wilson DM, Wilson TH. Transport properties of Asp-51-->Glu and Asp-120-->Glu mutants of the melibiose carrier of Escherichia coli. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1190:225-30. [PMID: 8142420 DOI: 10.1016/0005-2736(94)90078-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Asp-51-->Glu and Asp-120-->Glu mutants of the melibiose carrier of Escherichia coli were investigated for their cation/sugar cotransport properties. The carrier containing Glu-51 showed proton/melibiose cotransport but was extremely defective in Na+ or Li+ stimulation of sugar accumulation. On the other hand, the carrier containing Glu-120 had lost the ability to couple protons with melibiose uptake while retaining considerable Na+ or Li+ cotransport with melibiose (40-fold accumulation versus 90-fold for the wild type in the presence of Na+). It is concluded that both Asp-51 and Asp-120 are important for cation recognition.
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Affiliation(s)
- D M Wilson
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115
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16
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Replacement of alanine 58 by asparagine enables the melibiose carrier of Klebsiella pneumoniae to couple sugar transport to Na+. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)42221-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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17
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Padan E, Schuldiner S. Na+/H+ antiporters, molecular devices that couple the Na+ and H+ circulation in cells. J Bioenerg Biomembr 1993; 25:647-69. [PMID: 8144493 DOI: 10.1007/bf00770252] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Na+/H+ antiporters are universal devices involved in the Na+ and H+ circulation of both eukaryotes and prokaryotes, thus playing an essential role in the pH and Na+ homeostasis of cells. This review focuses on the major impact of the application of molecular biology tools in the study of the antiporters. These tools permit the verification of the role of the antiporters and provide insights into their unique biology. A novel signal transduction to Na+ involving nhaR, a positive regulator, controls the expression of nhaA in E. coli. A "pH sensor" regulates the activity of Na+/H+ antiporters, both in eukaryotes and prokaryotes. A most intricate signal transduction to pH involving phosphorylation steps controls the activity of nhel in higher mammals. The identification of Histidine 226 in the "pH sensor" of NhaA is a step forward towards the understanding of the pH regulation of these proteins.
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Affiliation(s)
- E Padan
- Division of Microbial and Molecular Ecology, Hebrew University of Jerusalem, Israel
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18
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Affiliation(s)
- B Poolman
- Department of Microbiology, University of Groningen, Haren, The Netherlands
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19
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Pourcher T, Zani M, Leblanc G. Mutagenesis of acidic residues in putative membrane-spanning segments of the melibiose permease of Escherichia coli. I. Effect on Na(+)-dependent transport and binding properties. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)53679-6] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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20
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Affiliation(s)
- M H Shirvan
- Teva Pharmaceutical Industries, Jerusalem, Israel
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21
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Hama H, Wilson T. Primary structure and characteristics of the melibiose carrier of Klebsiella pneumoniae. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(19)36971-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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22
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Mizushima K, Awakihara S, Kuroda M, Ishikawa T, Tsuda M, Tsuchiya T. Cloning and sequencing of the melB gene encoding the melibiose permease of Salmonella typhimurium LT2. MOLECULAR & GENERAL GENETICS : MGG 1992; 234:74-80. [PMID: 1495487 DOI: 10.1007/bf00272347] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The nucleotide sequence of the melB gene coding for the Na+ (Li+)/melibiose symporter of Salmonella typhimurium LT2 was determined, and its amino acid sequence was deduced. It consists of 1428 bp, corresponding to a protein of 476 amino acid residues (calculated molecular weight 52,800). The amino acid sequence is homologous to that of the melibiose permease of Escherichia coli K12, with 85% identical residues. All, except one, of the amino acid residues that have been reported to be important for cation or substrate recognition in the melibiose permease of E. coli are conserved in the melibiose permease of S. typhimurium. In addition, part of the sequence resembles the lactose permease of Streptococcus thermophilus, the animal glucose transporter (GLUT1), the plasmid-coded raffinose permease (RafB), and the NADH-ubiquinone oxidoreductase chain 4 (Nuo4) of Aspergillus amstelodami.
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Affiliation(s)
- K Mizushima
- Department of Microbiology, Faculty of Pharmaceutical Sciences, Okayama University, Japan
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23
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Wilson DM, Wilson TH. Asp-51 and Asp-120 are important for the transport function of the Escherichia coli melibiose carrier. J Bacteriol 1992; 174:3083-6. [PMID: 1569035 PMCID: PMC205965 DOI: 10.1128/jb.174.9.3083-3086.1992] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Asp-51 and Asp-120 of the Escherichia coli melibiose carrier on plasmid pKKMB were separately replaced by amber codons and transformed into eight amber suppressor strains, producing eight amino acid substitutions for each site. Glu-51 and Glu-120 were the only replacements in the carrier that allowed the cells to ferment melibiose and that showed transport of melibiose against a concentration gradient. Revertants to Glu-51 and Glu-120 show less activity than the wild type. The Asp-51 position is more crucial for Na(+)-stimulated melibiose accumulation than is the Asp-120 site.
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Affiliation(s)
- D M Wilson
- Department of Cellular and Molecular Physiology, Harvard Medical School, Boston, Massachusetts 02115
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Konings WN, Poolman B, Driessen AJ. Can the excretion of metabolites by bacteria be manipulated? FEMS Microbiol Rev 1992; 8:93-108. [PMID: 1558767 DOI: 10.1111/j.1574-6968.1992.tb04959.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Bacteria can release metabolites into the environment by various mechanisms. Excretion may occur by passive diffusion or by the reversal of the uptake process when the internal concentration of the metabolite exceeds the thermodynamic equilibrium level. In other cases, solutes are excreted against the concentration gradient by special extrusion systems. Their mode of energy coupling is different to that of the well-studied group of uptake systems. A thorough understanding of the transport processes will help to improve the excretion of metabolites of commercial interest, allow a more efficient production of metabolites in bulk quantities, and permit their exploitation to establish new markets.
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Affiliation(s)
- W N Konings
- Department of Microbiology, University of Groningen, Haren, The Netherlands
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25
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Sugar—Cation Symport Systems in Bacteria. ACTA ACUST UNITED AC 1992. [DOI: 10.1016/s0074-7696(08)62676-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/21/2023]
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26
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Abstract
There is a symbiotic relationship between the evolution of fundamental theory and the winning of experimentally-based knowledge. The impact of the General Chemiosmotic Theory on our understanding of the nature of membrane transport processes is described and discussed. The history of experimental studies on transport catalysed by ionophore antibiotics and the membrane proteins of mitochondria and bacteria are used to illustrate the evolution of knowledge and theory. Recent experimental approaches to understanding the lactose-H+ symport protein of Escherichia coli and other sugar porters are described to show that the lack of experimental knowledge of the three-dimensional structures of the proteins currently limits the development of theories about their molecular mechanism of translocation catalysis.
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27
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Okabe Y, Sakai-Tomita Y, Mitani Y, Tsuda M, Tsuchiya T. A novel mechanism of cation/substrate cotransport: Na+/H+/adenosine cotransport in Vibrio parahaemolyticus. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1059:332-8. [PMID: 1911824 DOI: 10.1016/s0005-2728(05)80218-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Adenosine is actively transported with Na+ in Vibrio parahaemolyticus (Sakai, Y., Tsuda, M., Tsuchiya, T. (1987) Biochim, Biophys. Acta 893, 43-48). The proton conductor carbonylcyanide m-chlorophenylhydrazone, CCCP, strongly inhibited active transport of adenosine at pH 8.5 as well as at pH 7.0. This seemed peculiar because the driving force, an electrochemical potential of Na+, is established by the Na(+)-extruding respiratory chain at pH 8.5 in this organism, although it is established by the function of the Na+/H+ antiporter at pH 7.0. This suggested that H+ might be involved in the adenosine transport. We detected H+ uptake induced by adenosine influx in V. parahaemolyticus cells in the presence of Na+, but not in its absence, suggesting the occurrence of Na+/H+/adenosine cotransport. We isolated formycin A-resistant mutants which showed defective adenosine transport. The mutation resulted in simultaneous losses of Na+ uptake and H+ uptake induced by adenosine. In revertants from these mutants the Na+ uptake and H+ uptake were restored simultaneously. The frequencies of reversion were in the order of 10(-7), indicating that the mutations were single mutations; namely that Na+/adenosine cotransport and H+/adenosine cotransport took place via the same carrier. Thus, we conclude that adenosine is transported by the novel mechanism of Na+/H+/adenosine cotransport in V. parahaemolyticus.
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Affiliation(s)
- Y Okabe
- Department of Microbiology, Faculty of Pharmaceutical Sciences, Okayama University, Japan
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28
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29
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Dibrov PA. The role of sodium ion transport in Escherichia coli energetics. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1056:209-24. [PMID: 1848102 DOI: 10.1016/s0005-2728(05)80052-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- P A Dibrov
- Department of Bioenergetics, A.N. Belozersky Laboratory of Molecular Biology and Bioorganic Chemistry, Moscow State University, U.S.S.R
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30
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King SC, Wilson TH. Towards an understanding of the structural basis of 'forbidden' transport pathways in the Escherichia coli lactose carrier: mutations probing the energy barriers to uncoupled transport. Mol Microbiol 1990; 4:1433-8. [PMID: 2287270 DOI: 10.1111/j.1365-2958.1990.tb02053.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Recent progress in the analysis of mutants of the Escherichia coli lactose carrier function is reviewed, with special emphasis on the structural basis for energy barriers which prevent 'forbidden' conformational changes. Mutations which break down the barriers to forbidden isomerizations involving the binary carrier:sugar (CS) and carrier:proton (CH) complexes have been obtained in several laboratories. These mutants allow uncoupled transport of H+ or galactoside in the lactose carrier which normally couples cation and sugar movement in a 1:1 stoichiometry. These uncoupled mutants appear to be associated with changes in both sugar and cation recognition, suggesting that the physical interactions forming the basis for co-substrate recognition and uncoupling are not independently variable. By postulating that translocation involves transformation of the stable intermediate of the co-transport cycle to unstable transition state conformations of the carrier, it is possible to consider the consequences of mutagenesis in terms of transition state theory. Consistent with several experimental observations, the analysis predicts in each mutant the occurrence of more than one abnormality in the transport cycle (such as changes in sugar recognition, cation recognition or the coupling reaction). We have called the general phenomenon a 'mutational double-effect' because any mutation which alters the Gibbs free energy change of one reaction in the transport cycle must affect the free energy change of at least one other reaction in this cycle.
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Affiliation(s)
- S C King
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115
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31
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Abstract
The cell membranes of various bacteria contain proton-linked transport systems for D-xylose, L-arabinose, D-galactose, D-glucose, L-rhamnose, L-fucose, lactose, and melibiose. The melibiose transporter of E. coli is linked to both Na+ and H+ translocation. The substrate and inhibitor specificities of the monosaccharide transporters are described. By locating, cloning, and sequencing the genes encoding the sugar/H+ transporters in E. coli, the primary sequences of the transport proteins have been deduced. Those for xylose/H+, arabinose/H+, and galactose/H+ transport are homologous to each other. Furthermore, they are just as similar to the primary sequences of the following: glucose transport proteins found in a Cyanobacterium, yeast, alga, rat, mouse, and man; proteins for transport of galactose, lactose, or maltose in species of yeast; and to a developmentally regulated protein of Leishmania for which a function is not yet established. Some of these proteins catalyze facilitated diffusion of the sugar without cation transport. From the alignments of the homologous amino acid sequences, predictions of common structural features can be made: there are likely to be twelve membrane-spanning alpha-helices, possibly in two groups of six; there is a central hydrophilic region, probably comprised largely of alpha-helix; the highly conserved amino acid residues (40-50 out of 472-522 total) form discrete patterns or motifs throughout the proteins that are presumably critical for substrate recognition and the molecular mechanism of transport. Some of these features are found also in other transport proteins for citrate, tetracycline, lactose, or melibiose, the primary sequences of which are not similar to each other or to the homologous series of transporters. The glucose/Na+ transporter of rabbit and man is different in primary sequence to all the other sugar transporters characterized, but it is homologous to the proline/Na+ transporter of E. coli, and there is evidence for its structural similarity to glucose/H+ transporters in Plants. In vivo and in vitro mutagenesis of the lactose/H+ and melibiose/Na+ (H+) transporters of E. coli has identified individual amino acid residues alterations of which affect sugar and/or cation recognition and parameters of transport. Most of the bacterial transport proteins have been identified and the lactose/H+ transporter has been purified. The directions of future investigations are discussed.
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Affiliation(s)
- P J Henderson
- Department of Biochemistry, University of Cambridge, United Kingdom
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32
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Affiliation(s)
- M C Botfield
- Department of Cellular and Molecular Physiology, Harvard Medical School, Boston, MA 02115
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33
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King SC, Wilson TH. Galactoside-dependent proton transport by mutants of the Escherichia coli lactose carrier: substitution of tyrosine for histidine-322 and of leucine for serine-306. BIOCHIMICA ET BIOPHYSICA ACTA 1989; 982:253-64. [PMID: 2546596 DOI: 10.1016/0005-2736(89)90062-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The lac Y genes from two Escherichia coli mutants, MAB20 and AA22, have been cloned in a multicopy plasmid by a novel 'sucrose marker exchange' method. Characterization showed that the plasmids express a lactose carrier with poor affinity for lactose. Neither mutant carried out concentrative uptake with methyl beta-D-galactopyranoside, lactose, or melibiose as the substrate. Nor did the mutants catalyze counterflow or exchange with methyl beta-D-galactopyranoside. Both mutants did, however, retain the capacity to carry out facilitated diffusion with lactose or melibiose. DNA sequencing revealed that MAB20 (histidine-322 to tyrosine) and AA22 (serine-306 to leucine) have amino acid substitutions within the putative 'charge-relay' domain thought to be responsible for proton transport. Galactoside-dependent H+ transport was readily measured in both mutants. We conclude, therefore, that the presence of a histidine residue at position 322 of the lactose carrier is not obligatory for H+ transport per se.
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Affiliation(s)
- S C King
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115
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Ohsawa M, Mogi T, Yamamoto H, Yamato I, Anraku Y. Proline carrier mutant of Escherichia coli K-12 with altered cation sensitivity of substrate-binding activity: cloning, biochemical characterization, and identification of the mutation. J Bacteriol 1988; 170:5185-91. [PMID: 3053649 PMCID: PMC211588 DOI: 10.1128/jb.170.11.5185-5191.1988] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Two putP mutants of Escherichia coli K-12 that were defective in proline transport but retained the binding activities of the major proline carrier were isolated (T. Mogi, H. Yamamoto, T. Nakao, I. Yamato, and Y. Anraku, Mol. Gen. Genet. 202:35-41, 1986). One of these mutations and three null-type mutations (K. Motojima, I. Yamato, and Y. Anraku, J. Bacteriol. 136:5-9, 1978) were cloned into a pBR322 putP+ hybrid plasmid (pTMP5) by in vivo recombination. Cytoplasmic membrane vesicles were prepared from the mutant strains and strains harboring pTMP5 putP plasmids, and the properties of the proline-binding reaction of the mutant putP carriers in membranes were examined under nonenergized conditions. The putP19, putP21, and putP22 mutations, which were mapped in the same DNA segment of the putP gene (Mogi et al., Mol. Gen. Genet. 202:35-41, 1986), caused the complete loss of proline carrier activity. The proline carriers encoded by the mutant putP genes, putP9 and putP32, and putP32 in pTMP5-32, which was derived from in vivo recombination with the putP32 mutation, had altered sodium ion and proton dependence of binding affinities for proline and were resistant to N-ethylmaleimide inactivation without changes in the specificities for substrates and alkaline metal cations. The nucleotide sequence of the putP32 lesion located on the 0.35-megadalton RsaI-PvuII fragment in the putP gene in pTMP5-32 was determined; the mutation changed a cytosine at position 1001 to a thymine, causing the alteration of arginine to cysteine at amino acid position 257 in the primary structure of the proline carrier. It was shown that this one point mutation was enough to produce the phenotype of pTMP5-32 by in vitro DNA replacement of the AcyI-PvuII fragment of the wild-type putP gene with the DNA fragment containing the mutated nucleotide sequence.
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Affiliation(s)
- M Ohsawa
- Department of Biology, Faculty of Science, University of Tokyo, Japan
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36
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Kawakami T, Akizawa Y, Ishikawa T, Shimamoto T, Tsuda M, Tsuchiya T. Amino acid substitutions and alteration in cation specificity in the melibiose carrier of Escherichia coli. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)68217-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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37
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Botfield MC, Wilson TH. Mutations that simultaneously alter both sugar and cation specificity in the melibiose carrier of Escherichia coli. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)37647-6] [Citation(s) in RCA: 78] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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38
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Boyer PD. Bioenergetic coupling to protonmotive force: should we be considering hydronium ion coordination and not group protonation? Trends Biochem Sci 1988; 13:5-7. [PMID: 2854307 DOI: 10.1016/0968-0004(88)90005-9] [Citation(s) in RCA: 109] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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39
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Hoshi T, Takuwa N, Abe M, Tajima A. Hydrogen ion-coupled transport of D-glucose by phlorizin-sensitive sugar carrier in intestinal brush-border membranes. BIOCHIMICA ET BIOPHYSICA ACTA 1986; 861:483-8. [PMID: 3768358 DOI: 10.1016/0005-2736(86)90458-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
In rabbit intestinal brush-border membrane vesicles, Na+-independent D-glucose uptake in the presence of an inside-negative transmembrane potential was found to be stimulated by an imposed pH gradient. Na+-independent, pH-dependent and phlorizin-sensitive D-glucose-evoked potentials could be recorded from isolated toad intestine. The obtained data suggest that phlorizin-sensitive D-glucose carriers of intestinal brush-border membrane can interact with H+ when Na+ is absent.
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40
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MacLeod RA. Salt requirements for membrane transport and solute retention in some moderate halophiles. FEMS Microbiol Lett 1986. [DOI: 10.1111/j.1574-6968.1986.tb01850.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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