Disease relevance of leucine

• In the present studies, using a series of peptides derived from CS-1, we identify the tripeptide leu-asp-val (LDV), as the minimal peptide capable of supporting stable lymphocyte or melanoma cell adhesion [1].
• This article presents evidence that starvation for leucine in an Escherichia coli auxotroph triggers metabolic activities that specifically target the leu operon for derepression, increased rates of transcription, and mutation [2].
• These mutations map at approximately 3 map units, phage P22 cotransducible with leu [3].
• leu operon of Salmonella typhimurium is controlled by an attenuation mechanism [4].
• The left end of the substitution is usually a crossover that recombines the IS2 element in the prophage with an E. coli IS2 at 8.5 minutes, near the lac gene, or with a second IS2 located counterclockwise from leu at 2 minutes, generating duplications of at least 200,000 bases [5].

High impact information on leucine

• The suppressor-cytotoxic (leu 2a) and helper-inducer (leu 3a) subsets identified by phycoerythrin-labeled monoclonal antibodies contained substance P-reactive T-lymphocytes at respective mean frequencies of 10 and 18% [6].
• Protein synthetic error frequency, determined in cell-free extracts as delta leu/delta phe incorporation following poly(U) stimulation, has been found to decrease progressively in several strains of human diploid fibroblasts during their limited replicative lifespan [7].
• When the leu operon was induced by isopropyl-D-thiogalactoside, both leuB mRNA abundance and leuB- reversion rates increased [2].
• These investigations suggest that guanosine tetraphosphate may contribute as much as attenuation in regulating leu operon expression and that higher rates of mutation are specifically associated with the derepressed leu operon [2].
• Transcription attenuation in Salmonella typhimurium: the significance of rare leucine codons in the leu leader [8].

Chemical compound and disease context of leucine

• This tt' termination pattern at the distal end of the ilvGMEDA operon is similar to that of the trp operon of E. coli and the leu operon of Salmonella typhimurium [9].
• Erwinia sp. donors harboring pULB113 complemented mutations in various biosynthetic and catabolic genes (arg, gal, his, leu, met, pro, pur, thy) in Escherichia coli recA strains [10].
• The influence of pre-exposure to low doses of ethylene oxide (EtO) on the frequency of leu+ revertants in the E. coli strain, WU36-10, and its excision-repair-deficient mutant, WU36-10-89, after treatment with high doses of EtO, was studied [11].
• In mice given cyclophosphamide followed by human TILs i.p., the TILs were demonstrated at 7 days in the SCID peritoneum (leu 4 = 4%) and at 2 days in the SCID spleen (leu 4 = 2%) [12].
• Our data show that a single leucine to serine replacement at only one of the four CUG codons encoded by the BMV RNA-4 gene is responsible for the aberrant migration of the BMV coat protein on SDS-PAGE, suggesting that this amino acid substitution (ser for leu) significantly alters the structure of the virion coat protein [13].

Biological context of leucine

• To further demonstrate that derepression increased mutation rates, the chromosomal leu operon was placed under the control of the inducible tac promoter [2].
• The nucleotide sequence of the control region of the leu operon of Salmonella typhimurium was determined [4].
• The trinucleotide repeat mutation changed 5'-AGT GTG GTG GTG-3' at codons 215-218 to 5'-AGT TGG TTG GTG GTG-3'. The predicted protein would be elongated by one amino acid (val216-->trp leu) without a change in charge [14].
• Invariant leu preceding turn motif phosphorylation site controls the interaction of protein kinase C with hsp70 [15].
• The related replicon in Buchnera of Pemphigidae, which lacks leuABCD, appears to represent the ancestral condition, implying that the plasmid location of the leu genes arose after the Pemphigidae diverged from other aphid families [16].

Anatomical context of leucine

• While "constitutive" release of CSFs from monocytes was apparent from both the leu M3+, HLA-DR+ and the leu M3+, HLA-DR- (low density or negative DR) fractions, enhanced release of CSFs in response to rhuTNF-alpha or rhuIFN-gamma was confined to the leu M3+, HLA-DR+ population of cells [17].
• This is evidenced by pulse labeling studies of erythroblasts from a patient with HPP associated with a homozygous state for spectrin alpha I/46 mutation (leu-pro mutation at AA 207 of alpha-spectrin) [18].
• The results from these studies indicate that leu-pro-pro-ser-arg (residues 351 to 355) retained the B cell differentiation-inducing properties of p23; however, expression of activity by this sequence was markedly influenced by N-flanking sequences [19].
• In addition to VIP-IR and CGRP-IR, we examined the sweat gland innervation for several neuropeptides which have been described in noradrenergic sympathetic neurons including neuropeptide Y, somatostatin, substance P, and leu- and met-enkephalin; these peptides were not evident in either developing or mature sweat gland axons [20].
• The effects of leu- and met-enkephalin were investigated on the node of Ranvier of isolated nerve fibers of frog under current and voltage clamp conditions [21].

Associations of leucine with other chemical compounds

• Mutant receptors lacking almost the entire cytoplasmic domain of IL-3R alpha [IL-3R alpha(CD)] or carrying a substitution of trp for leu in the membrane proximal leu-ser-x-trp-ser (LSXWS) box bound 125I-IL-3 with nearly the same affinity as wild-type IL-3R alpha [22].
• In this study, we demonstrate that AT4 receptor ligands, including Ang IV, Nle1-Ang IV, divalinal-Ang IV, and the structurally unrelated LVV-hemorphin-7, are all potent inhibitors of IRAP catalytic activity, as assessed by cleavage of leu-beta-naphthylamide by recombinant human IRAP [23].
• The m1G deficiency induced 24 and 26% reductions in the growth rate and polypeptide chain elongation rate, respectively, in morpholinepropanesulfonic acid (MOPS)-glucose minimal medium at 37 degrees C. The expression of the leuABCD operon is controlled by the rate with which tRNA(2Leu) and tRNA(3Leu) read four leucine codons in the leu-leader mRNA [24].
• This strain was previously found to receive Flac plasmid (N. Datta and R.W. Hedges, J. Gen Microbiol. 70:453-460, 1972). ilv, leu, met, arg, and his auxotrophs were complemented by plasmids carrying isofunctional genes; trp mutants were not complemented or were very poorly complemented [25].
• Comparison of hemoglobins Wood (alpha 2 beta 2 97 leu) and Malmö (alpha 2 beta 2 97 gln). Diagnostic value of citrate agar electrophoresis [26].

Gene context of leucine

• Molecular cloning, genomic organization, developmental regulation, and a knock-out mutant of a novel leu-rich repeats-containing G protein-coupled receptor (DLGR-2) from Drosophila melanogaster [27].
• A linear DNA fragment containing the LEU2 gene was inserted at the breakpoints of an 800-base pair deletion of the iron-sulfur protein gene and used to transform a leu- yeast strain [28].
• These same sights were localized using an immunoperoxidase sequence with a rabbit polyclonal antibody to the leu 60-leu 98 fragment of aFGF (aFGFfr) with less background [29].
• We also constructed an integration vector, which consisted of the Escherichia coli plasmid vector pBluescript and a 2.1-kb segment of the T. thermophilus leu operon sequence, for the integration of a foreign gene into a chromosome of the thermophile. pyrE and leuB genes were used as probes to test the integration vector [30].
• Chromosomal fragments cloned because they complemented this mutation were found to complement leu mutations, and vice versa, but none of these fragments complemented a tyrB mutation [31].

Analytical, diagnostic and therapeutic context of leucine

• These data indicate that although the leu-pro-pro-ser-arg sequence is able to provide both required signals for p23-induced Ig secretion in spleen cell cultures, there may be subtle differences in how the cell types involved in this response interact with and/or are activated by this sequence [19].
• Sequence analysis of DNA from these phage demonstrated that each contains a single base change in the leu attenuator [32].
• Peripheral blood and bronchoalveolar lavage lymphocyte subpopulations have been evaluated in 14 patients with pulmonary sarcoidosis and eight normal subjects, monoclonal antibodies of the leu series being used [33].
• The leader region from S. typhimurium was altered by site-directed mutagenesis to produce constructs having between one and seven adjacent Leu codons, all CUA. leu operon expression was measured in strains containing six of these constructs, each integrated into the chromosome in a single copy [34].
• 6. HPLC fractions from regions with retention times corresponding to authentic leu- or met-enkephalin showed physiologic responses similar to those of DALEU and DAMET, respectively [35].

References