Production of multiple wheat-rye 1RS translocation stocks and genetic analysis of LMW subunits of glutenin and gliadins in wheats using these stocks

Summary A triple (1AL.1RS/1BL.1RS/1DL.1RS) and three double (1AL.1RS/1BL.1RS, 1AL.1RS/1DL.1RS, 1BL.1RS/1DL.1RS) wheat-rye 1RS translocation stocks were isolated from a segregating population using the Gli-1, Tri-1 and Sec-1 seed proteins as genetic markers. These stocks carried 42 chromosomes and formed the expected multivalents (frequency of 14–25%) at metaphase 1. They gave floret fertility ranging from 40–60%. These stocks were subsequently used to determine the genetic control of low-molecular-weight (LMW) glutenin subunits in Chinese Spring and Gabo by means of two-step one-dimensional SDS-PAGE. All of the B subunits and most of the C subunits of glutenin were shown to be controlled by genes on the short arms of group-1 chromosomes in these wheats. The other C subunits were not controlled by group-1 chromosomes. The triple translocation line served as a suitable third parent in producing test-cross seeds for studying the inheritance of the LMW glutenin subunits and gliadins in wheat cultivars, e.g. Chinese Spring and Orca. The segregation patterns of the LMW glutenin subunits in these cultivars revealed that the subunits were inherited in clusters and that their controlling genes (Glu-3) were tightly linked with those controlling gliadins (Gli-1). The LMW glutenin patterns d, d and e in Orca segregated as alternatives to the patterns a, a and a in Chinese Spring controlled by Glu-A3, Glu-B3 and Glu-D3 loci on chromosome arms 1AS, 1BS and 1DS, respectively, thus indicating that these patterns were controlled by allelic genes at these loci.     

Primary structure of the majorO-glycosidically linked carbohydrate unit of human von Willebrand factor

A reduced tetrasaccharide chain was obtained from human von Willebrand factor (vWF) by mild alkaline borohydride treatment. The purification of thisO-glycosidically-linked oligosaccharide was achieved by serial affinity chromatography on immobilized concanavalin A andLens culinaris agglutinin and finally gel filtration. Its structure was determined by a combination of methylation studies and 500 MHz¹H-NMR spectroscopy to be: NeuAc(2-3)Gal(1-3)[NeuAc(2-6)]GalNAc-ol.Abbreviations ConA concanavalin A - LCA Lens culinaris agglutinin - vWF von Willebrand factor - NeuAc N-acetylneuraminic acid - Gal d-galactose - GalNAc-ol N-acetyl-d-galactosaminitol - HMW high molecular weight - LMW low molecular weight     

Erratum: Cloning and sequencing of the phycocyanin gene from Spirulina maxima and its evolutionary analysis

The genes were cloned for the two apoprotein subunits, and ,of phycocyanin from the cyanobacterium Spirulina maxima = Arthrospiramaxima) strain F3. The - and -subunit gene-coding regionscontain 489 bp and 519 bp, respectively. The -subunit gene is upstreamfrom the -subunit gene, with a 111-bp segment separating them.Similarities between the -subunits of S. maxima and nine othercyanobacteria were between 58% and 99%, as were those between the -subunits. The maximum similarity between the - and -subunits from S. maxima was 27%.     

Selectively 13C-enriched DNA: Evidence from 13C1′ relaxation rate measurements of an internal dynamics sequence effect in the lac operator

Summary In order to study some internal dynamic processes of the lac operator sequence, the ¹³C-labeled duplex 5d(C₀G₁C₂T₃C₄A₅C₆A₇A₈T₉T₁₀) · d(A₁₀A₉T₈T₇G₆T₅G₄A₃G₂C₁G₀)3 was used. The spreading of both the H1 and C1 resonances brought about an excellent dispersion of the ¹H1-¹³C1 correlations. The spinlattice relaxation parameters R(C_z), R(C_x,y) and R(H_zC_z) were measured for each residue of the two complementary strands, except for the 3-terminal residues which were not labeled. Variation of the relaxation rates was found along the sequence. These data were analyzed in the context of the model-free formalism proposed by Lipari and Szabo [(1982) J. Am. Chem. Soc., 104, 4546–4570] and extended to three parameters by Clore et al. [(1990) Biochemistry, 29, 7387–7401; and (1990) J. Am. Chem. Soc., 112, 4989–4991]. A careful analysis using a least-squares program showed that our data must be interpreted in terms of a three-parameter spectral density function. With this approach, the global correlation time was found to be the same for each residue. All the C1-H1 fragments exhibited both slow (_s = 1.5) and fast (_f = 20 ps) restricted libration motions (S _inf2 ^sups =0.74 to 1.0 and S _inf2 ^supf =0.52 to 0.96). Relaxation processes were described as governed by the motion of the sugar relative to the base and in terms of bending of the whole duplex. The possible role played by the special structure of the AATT sequence is discussed. No evident correlation was found between the amplitude motions of the complementary residues. The 5-terminal residues showed large internal motions (S²=0.5), which describe the fraying of the double helix. Global examination of the microdynamical parameters S _inf2 ^supf and S _inf2 ^sups along the nucleotide sequence showed that the adenine residues exhibit more restricted fast internal motions (S _inf2 ^supf =0.88 to 0.96) than the others, whereas the measured relaxation rates of the four nucleosides in solution were mainly of dipolar origin. Moreover, the fit of both R(C_z) and R(HzC_z) experimental relaxation rates using an only global correlation time for all the residues, gave evidence of a supplementary relaxation pathway affecting R(C_x,y) for the purine residues in the (53) G₄A₃ and A₁₀A₉T₈T₇ sequences. This relaxation process was analyzed in terms of exchange stemming from motions of the sugar around the glycosidic bond on the millisecond time scale. It should be pointed out that these residues gave evidence of close contacts with the protein in the complex with the lac operator [Boelens et al. (1987) J. Mol. Biol., 193, 213–216] and that these motions could be implied in the lac-operator-lac-repressor recognition process.     

Inheritance and linkage relationships of glutamate oxaloacetate transaminase isoenzymes in apple

Summary Four zones of enzymatic activity for glutamate oxaloacetate transaminase (GOT) were found in apple tissue. A dimeric gene, GOT-1, determining the fastest migrating zone, was identified. Six alleles were found, including a near null allelle which produced detectable heterodimeric bands but not homodimeric bands. A marked deficit or absence of certain geno-types in all backcrosses and in some crosses between unrelated varieties was attributed to the close linkage (r=0.02±0.005) of GOT-1 with the incompatibility S locus. GOT-1 was also closely linked with the isocitrate dehydrogenase locus IDH-1 (0.03±0.01). Proposed incompatibility genotypes for four cultivars, and the linked GOT-1 alleles are Cox: S ₁ b/S ₂ d, Idared: S ₃ a/S ₄ c, Fiesta: S ₃ a/S ₂ d and Kent: S ₃ a/S ₁ b.The results reported in this paper are part of a PhD Thesis by the first author     

High molecular weight glutenin subunit variation in Triticum turgidum var. dicoccum

Summary Variation in high molecular weight (HMW) glutenin subunit composition among 167 accessions of dicoccum wheat (Triticum turgidum L. var. dicoccum Schrank) of diverse origins was investigated using one-dimensional sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). A total of 20 alleles were identified, and 9 of them were found to be different from those previously detected by Payne and Lawrence (1983 b) in hexaploid wheat (Triticum aestivum L.). The newly discovered alleles enhance the genetic variability available to improve the industrial quality of wheats and some of them may facilitate basic research on the relationship of industrial quality with HMW glutenin subunit number. The novel variants include a GLU-A1 encoded subunit which has higher molecular mass than any other so far described in tetraploid and hexaploid wheats, and a null GLU-B1 allele. Dicoccums containing neither GLU-A1- nor GLU-B1-encoded subunits were also identified. A comparison of the mean number of HMW glutenin subunits contained in various primitive and modern domesticated wheats of different ploidy levels and the identification of wheats containing no HMW glutenin subunits suggest that the occurrence of null GLU-1 alleles in these species depends on chance rather on an inherent tendency on the part of modern polyploid wheats to suppress the activity of redundant GLU-1 genes.     

Specificity of an antibody to a subunit of high-molecular-weight storage protein from wheat seed and its reaction with other cereal storage proteins (prolamins)

An antiserum to subunit 2 from the high-molecular-weight (HMW) subunits of the glutenin fraction of Triticum aestivum cv. Highbury was shown to react with related subunits from other cultivars of wheat. The reaction was measured quantitatively by laser nephelometry in polyethylene glycol phosphate-buffered saline after dissolving the HMW fraction in 0.1 M acetic acid; urea used to dissolve the HMW prolamins inhibited the reaction, in some cases at the low concentration of 0.06 M. A study of the comparative reactions of other cereal prolamins was made. D hordein, the homologous HMW protein of barley, showed less reaction, which was more inhibited by urea than the wheat subunits. Some -gliadins from the wheat cultivars Chinese Spring and Cheyenne reacted more strongly than the injected fraction and there was less inhibition by urea. A-, - and ₃ of wheat also reacted with the antiserum while a secalin of rye of M_r 40000 gave a weak reaction.Abbreviations HMW high molecular weight - PAGE polyacrylamide-gel electrophoresis - PBS phosphate-buffered saline - PE pyridylethylated - SDS sodium dodecyl sulphate     

The addition of Dasypyrum villosum (L.) Candargy chromosomes to durum wheat (Triticum durum Desf.)

Summary Six monosomic addition lines were produced in which different Dasypyrum villosum (L.) Candargy chromosomes were added to the chromosome complement of Triticum durum Desf. cv. Creso. Each added alien chromosome was found to have a specific effect on plant morphology and fertility. Transmission rate varied widely (from 7.5 to 27.7%) among the six univalent chromosomes. Different monotelosomic addition plants derived by a relatively high frequency of chromosome misdivision were isolated. The addition lines should be useful for studying Dasypyrum chromosome homoeology and the introduction of alien variation into durum and common wheats.Research supported by a grant from the Italian Research Council for Finalized Project IPRA. Sub-project Plant Breeding, Paper No. 1095     

Increased erythritol production in Torula sp. by Mn2+and Cu2+

The production of erythritol and the erythritol yield from glucose by Torula sp. were improved, in increasing order, by supplementing with 10 mg MnSO₄4H₂O l^–1, 2 mg CuSO₄5H₂O l^–1, and both 10 mg MnSO₄4H₂O l^–1 and 2 mg CuSO₄5H₂O l^–1. Mn²⁺ decreased the intracellular concentration of erythritol, whereas Cu²⁺ increased the activity of erythrose reductase in cells. These results suggest that Mn²⁺ altered the permeability of cells, whereas Cu²⁺ increased the activity of erythrose reductase in cells.     

Production and genetic characterization of near-isogenic lines in the bread-wheat cultivar Alpe

Two biotypes of the bread-wheat cultivar Alpe were shown to possess contrasting alleles at each of the glutenin (Glu-B1, Glu-D1, Glu-B3 and Glu-D3) and gliadin (Gli-B1 and Gli-D1) loci on chromosomes 1B and 1D. Fourteen near-isogenic lines (NILs) were produced by crossing these biotypes and used to determine the genetic control of both low-molecular-weight (LMW) glutenin subunits and gliadins by means of one-dimensional or two-dimensional electrophoresis. Genes coding for the B, C and D groups of EMW subunits were found to be inherited in clusters tightly linked with those controlling gliadins. Southern-blot analysis of total genomic DNAs hybridized to a -gliadin-specific cDNA clone revealed that seven NILs lack both the Gli-D1 and Glu-D3 loci on chromosome 1D. Segregation data indicated that these null alleles are normally inherited. Comparison of the null NILs with those possessing allele b at the Glu-D3 locus showed one B subunit, seven C subunits and two D subunits, as fractionated by two-dimensional A-PAGExSDS-PAGE, to be encoded by this allele. Alleles b and k at Glu-B3 were found to code for two C subunits plus eight and six B subunits respectively, whereas alleles b and k at Gli-B1 each controlled the synthesis of two -gliadins, one and two -gliadins. The novel Gli-B5 locus coding for two -gliadins was shown to recombine with the Gli-B1 locus on chromosome 1B. The two-dimensional map of glutenin subunits showed -gliadins encoded at the Gli-A2 locus on chromosome 6A. The use of Alpe NILs in the study of the individual and combined effects of glutenin subunits on dough properties is discussed.Research supported by a grant from the Commission of the European Communities, ECLAIR programme, Contract AGRE 0052     

The effect of additions ofAegilops longissima chromosomes on grain protein in common wheat

Summary The effect of various chromosomes ofAegilops longissima when added to the common wheat cultivar Chinese Spring was evaluated at two levels of nitrogen fertilization for absolute and relative amount of protein in the grain. All the added chromosomes ofAe. longissima increased protein percentage: protein increase by chromosomes D, C and A averaged 3.8% while that by chromosomes F, E, G and B averaged 1.7%. Addition lines F, D and C had a significantly higher protein weight per grain. On the other hand, lines A, E and G had reduced grain protein weight per grain as compared with that of Chinese Spring. Line C carries the HMW glutenin and some of the gliadin subunits ofAe. longissima. The effect of this line, however, and obviously that of the other lines on protein content was through genes controlling the level of storage protein rather than through genes that code directly for these proteins. Nitrogen fertilization affected protein content and the relative amount of the various protein fractions in a similar manner in every addition line. When high levels of nitrogen fertilization were compared to low ones, the relative amount of the HMW glutenins remained constant while that of HMW gliadins increased and that of the LMW subunits decreased. In contrast to the nitrogen effect, increase in protein content by the addition oflongissima chromosomes did not change the relative amounts of the various protein fractions.The paper is based on a portion of a dissertation to be submitted by A.A.L. in partial fulfillment of the PhD requirements in the Feinberg Graduate School, The Weizmann Institute of Science, RehovotThe Marshall and Edith Korshak Professor of Plant Cytogenetics     

Linkage mapping of prolamin and isozyme genes on the 1Sl chromosome of Aegilops longissima

The storage proteins and isozymes of two accessions of Aegilops longissima, and the F₂ progeny from the cross between them, were analyzed. Six loci were identified on the 1S^l chromosome: Glu-S ^l 1 (coding for HMW subunits of glutenin), Gpi-S ^l 1 (coding for a Gpi isozyme), Glu-S ^l 3 (coding for LMW subunits of glutenin), Gli-S ^l 1 (coding for gliadins) and two, so far, not described new loci Gli-S ^l 4 and Gli-S ^l 5. The Gli-S ^l 4 locus codes for a -gliadin and the Gli-S ^l 5 codes for a gliadin with mobility in the -region. The genetical distances found between the six loci allowed the establishment of the following gene order on the 1S^l chromosome: Glu-S ^l 1 —centromere —Gpi-S ^l 1 — Gli-S ^l 4 — Gli-S ^l 3 — Gli-S ^l 1 -Gli-S ^l 5.     

Polysaccharide-enriched fraction isolated from Duchesnea chrysantha protects against oxidative damage

Reactive oxygen species (ROS)-related oxidative damages have been implicated in a wide variety of the pathological processes such as atherosclerosis, inflammation and carcinogenesis. A polysaccharide-enriched fraction (PEF) was isolated from Duchesnea chrysantha, a herbaceous plant, and its antioxidant activity was demonstrated using several assay systems in vitro. The PEF effectively inhibited Cu²⁺-stimulated low density lipoprotein oxidation in a concentration-dependent way and retarded the conjugated diene formation with the enhancement of the lag phase during oxidation. An assay for DNA strand breaks showed that PEF strongly protected DNA against damage caused by UV or by OH or O₂ ^– generated in the metal-catalyzed oxidation system. PEF effectively inhibited Nitroblue Tetrazolium reduction mediated by O₂ ^– in a dose-dependent manner. It also competed with 2-deoxy-d-ribose in absorbing OH generated by -irradiation (600 Gy) and thus inhibited the formation malondialdehyde. In conclusion, these evidences indicate that PEF may act as an antioxidant to scavenge O₂ ^–, OH or LO₂ directly. Our findings suggest the possibility that it may play a role as a potential therapeutic antioxidant in treatment of oxidative damage-derived diseases.     

Adventitious shoot regeneration from leaf explants of tissue cultured and greenhouse-grown raspberry

Adventitious shoot regeneration was observed using leaf-petiole explants from shoot-proliferating cultures of Comet red raspberry (Rubus idaeus L.). A maximum regeneration rate of 70% (3.7 shoots/explant) was obtained using 4.5–9.1 M (1–2 mg l^–1) N-phenyl-N-1,2,3-thiadiazol-5-ylurea (thidiazuron or TDZ) with 2.5–4.9 M (0.5–1 mg l^–1) 1H-indole-3-butanoic acid (IBA) or 2.3 M (0.5 mg l^–1) TDZ with 4.9 M (1 mg l^–1) IBA in modified Murashige-Skoog medium. TDZ was more effective than N-(phenylmethyl)-1H-purin-6-amine (BA) at promoting regeneration in combinations tested with IBA (maximum 50% regeneration rate; 1.8 shoots/explant). Variation in the agar concentration or incubation temperature, orientation or scoring of the leaf-petiole explants and use of separate leaf or petiole explants had no effect on shoot regeneration. Incubation in the dark for 1, 2 or 3 weeks prior to growth in the light did not influence the percent regeneration rate but depressed the number of adventitious shoots. Explant source, from micropropagated shoots or greenhouse-grown plants, had an effect on shoot regeneration that was genotype dependent. Only 8 of 22 (36%) raspberry cultivars were capable of regeneration from leaf explants derived from greenhouse-grown plants.     

Export and activity of hybrid FhuA''-''Iut receptor proteins and of truncated FhuA'' proteins of the outer membrane of Escherichia coli

Summary The FhuA protein in the outer membrane of Escherichia coli serves as a multifunctional receptor for the phages T5, T1, 80, for colicin M, for ferrichrome (Fe³⁺-siderophore) and for the structurally related antibiotic, albomycin. To determine structural domains required for these receptor functions and for export, a fusion protein between FhuA and Iut (receptor for Fe³⁺-aerobactin and cloacin DF13) was constructed. In the FhuA-Iut hybrid protein, 24 amino acids of FhuA were replaced by 19 amino acids, 18 of which were from Iut. The number of plaque forming units of phage T5 and T1 on cells expressing FhuA-Iut was nearly as high as on cells expressing plasmid-encoded wild-type FhuA. However, 10⁷-fold higher concentrations of phage 80 and 10³ times more colicin M were required to obtain a zone of growth inhibition. Truncated FhuA proteins in which the last 24 amino acids at the carboxy-terminus were replaced by 16 (FhuA2) or 3 (FhuAT) amino acids could hardly be detected on polyacrylamide electrophoretograms of outer membrane proteins, due to proteolytic degradation. Sensitivity of cells expressing FhuA2 to phage T5 and T1 was reduced by several orders of magnitude and sensitivity to phage 80 and colicin M was totally abolished. In contrast, cells expressing FhuAT were nearly as sensitive to phage T5, T1, and 80 and to colicin M as cells containing FhuA-Iut. None of the constructs could grow on ferrichrome as sole iron source and none was sensitive to albomycin. Ferrichrome did not inhibit binding of T5 to TonB^– cells expressing FhuA-Iut (as it did in FhuA⁺ cells) due to the lack of ferrichrome binding. It is concluded that very small deletions (relative to the size of FhuA with 714 amino acids) at the C-terminal end render FhuA susceptible to proteolytic cleavage. The C-terminal alterations affect sensitivity to FhuA-specific agents very differently. Apparently, the C-terminus is a very important part of FhuA regarding stability and activity. Expression of active FhuA and partially inactive FhuA derivatives in the same cell revealed no negative complementation, suggesting a FhuA monomer as functional unit.     

The chromosomal locations and linkage relationships of the structural genes for the prolamin storage proteins (secalins) of rye

Summary Rye secalins are a polymorphic mixture of polypeptides which are classified into four major groups. Previous studies have shown that the structural genes for two of the groups (the -secalins and 40K -secalins) are located on the short arm of chromosome 1R and those for a third group (the high molecular weight secalins) on the long arm of the same chromosome. Analysis of F₂ grain from crosses between inbred lines of S. cereale shows that the structural genes for the -secalins (designated Sec 1) and the high molecular weight secalins (designated Sec 3) are loosely linked (40.8 ±3.76% recombination, 57.4 ± 11.30 cM). Analysis of wheat rye addition lines shows that the structural genes for the 75K -secalins are present on chromosome 2R. This locus is provisionally designated Sec 2. These genes are probably derived from those for the 40K -secalins by duplication, divergence and translocation. Analysis of secalin fractions from wild species of rye shows that all contain 75K -secalins, indicating that the duplication and divergence, if not the translocation, occurred before speciation of the genus.     

A 500-MHz1H-NMR study on theN-linked carbohydrate chain of bromelain

The 500-MHz¹H-NMR characteristics of theN-linked carbohydrate chain Man1-6[Xyl1-2]Man1-4GlcNAc1-4[Fuc1-3]GlcNAc1-NAsn of the proteolytic enzyme bromelain (EC 3.4.22.4) from pineapple stem were determined for the oligosaccharide-alditol and the glycopeptide, obtained by hydrazinolysis and Pronase digestion, respectively. The¹H-NMR structural-reporter-groups of the (1–3)-linked fucose residue form unique sets of data for the alditol as well as for the glycopeptide.     

Light dependence of protoplasmic streaming in Nitella flexilis L. as measured by means of laser-velocimetry

Laser-velocimetry was applied in order to study the effect of light on the velocity of protoplasmic streaming (pps) in Characean cells. A change from dark to light (= 6 W · m^–2) leads to an acceleration of streaming by about 15–30% with a time-constant of approx. 300 s. The transition from light to dark causes a transient decrease of velocity below the original dark level. This response occurs with a time constant of about 500 s. It returns to its initial value with a time-constant of about 2000 s. This may indicate that a control loop of cytosolic homeostasis takes a decrease in pCa more seriously than an increase. A possible involvement of temperature effects caused by illumination was excluded by measuring the influence of temperature. Steady-state velocity of streaming changed by 5% per 1° C. Irradiation with infra-red light ( > 780 nm) did not cause a change in velocity. The absence of a light effect on streaming velocity in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) shows that photosynthesis and not phytochrome is involved. The role of light-induced changes of pCa is discussed, especially with respect to the hypothesis of Vanselow and Hansen (1989, J. Membr. Biol. 110, 175–187) that photosynthesis acts on the plasmalemma K⁺-channel via light-induced uptake of Ca²⁺ into the chloroplasts.Abbreviations and Symbols ASF auto structure function - DCMU 3-(3,4-dichlorophenyl)-1,1-dimethylurea - pps protoplasmic streaming - _L, _D, _C time-constants of the light and dark responses, and of a putative Ca-control system Financial support by the Deutsche Forschungsgemeinschaft is gratefully acknowledged. The first author was granted a scholarship by the state of Schleswig-Holstein. We are indebted to Prof. Dr. G. Pfister for technical advice and helpful discussions and to Mrs. E. Götting for drawing the figures.     

Chromosome structure of Triticum longissimum relative to wheat

Homoeologous pairing at meiotic metaphase I was analyzed in T. longissimum x T. aestivum hybrids in order to reconfirm the homoeologous relationships of T. longissimum chromosomes to wheat. Hybrids between T. longissimum and Chinese Spring carrying the Ph1 gene or theph1b mutation, which showed low and high pairing levels, respectively, were used. Chromosome arms associated at metaphase I were identified by C-banding. The homoeology of chromosomes 1S ^l , 2S ^l , 3S ^l , 5S ^l and 6S ^l to wheat group 1,2, 3, 5, and 6 chromosomes, respectively, was confirmed. Chromsome arms 4S ^l S and 7S ^l S showed normal homoeologous relationships to wheat. The 4S ^l L arm carries a translocated segment from 7S ^l L relative to wheat. The 7S ^l L arm seldom paired, likely because this arm lost a relatively long segment and received a very short segment in the interchange with 4S ^l L. Available data suggest that translocation 4S ^l L/7S ^l L arose in the evolution of T. longissimum, which implies that this species was not the donor of the B genome of wheat.     

Bacterial siderophores : structure and NMR assignment of pyoverdins Pa,siderophores ofPseudomonas aeruginosa ATCC 15692

Summary In iron-deficient conditions,Pseudomonas aeruginosa ATCC 15692 synthesizes two major siderophores, pyoverdins Pa and pyoverdin Pa B. Two other compounds, pyoverdin Pa A (occurring from hydrolysis of pyoverdin Pa during the culture) and pyoverdin Pa C (occurring artifactually during the purification procedure) were also isolated. All these compounds possess the same partly cyclic peptide chain wherel-Orn(OH · HCO) isN -formyl,N -hydroxy-l-ornithine. The chain is bound to a chromophore derived from 2,3-diamino-6,7-dihydroxyquinoline and having the (S) configuration. The four pyoverdins differ only in the acyl substituent bound to the nitrogen atom bound to carbon C3 of the chromophore. This is succinamide (pyoverdin Pa), succinic acid (pyoverdin Pa A), methyl succinate (pyoverdin Pa C) and 2-oxoglutaric acid (pyoverdin Pa B). The complete¹H- and¹³CNMR assignments, using two-dimensional total correlation NMR spectroscopy (TOCSY) and rotating-frame Overhauser enhancement spectroscopy (ROESY) procedures, as well as¹H-¹³C correlations, are reported. The complete sequence of the peptide using CH-NH correlations was achieved by NMR and confirmed the partly cyclic structure earlier reported using fast-atom-bombardment mass spectrometry (FAB-MS) on the siderophores and their dansylated fragments [Briskot G, Taraz K, Budzikiewicz H (1989)Liebigs Ann Chem: 375–384]. The use of these NMR procedures appears to be a tool of choice and a complementary approach to FAB-MS in the structure determination of some complex pyoverdins.Abbreviations Ser serine - Arg arginine - Thr ethreonine - Lys lysine - OHOrn N -hydroxyornithine - Chr chromophore