The substrate of the glucose-6-phosphate dehydrogenase of Pseudomonas aeruginosa provides structural stability.

In general, eukaryotic glucose-6-phosphate dehydrogenases (G6PDHs) are structurally stabilized by NADP+. Here we show by spectrofluorometric analysis, thermal and urea denaturation, and trypsin proteolysis, that a different mechanism stabilizes the enzyme from Pseudomonas aeruginosa (PaG6PDH) (EC 1.1.1.363). The spectrofluorometric analysis of the emission of 8-anilino-1-naphthalenesulfonic acid (ANS) indicates that this stabilization is the result of a structural change in the enzyme caused by G6P. The similarity between the Kd values determined for the PaG6PDH-G6P complex (78.0 ±â€¯7.9 µM) and the K0.5 values determined for G6P (57.9 ±â€¯2.5 and 104.5 ±â€¯9.3 µM in the NADP+- and NAD+-dependent reactions, respectively) suggests that the structural changes are the result of G6P binding to the active site of PaG6PDH. Modeling of PaG6PDH indicated the residues that potentially bind the ligand. These results and a phylogenetic analysis of the amino acid sequences of forty-four G6PDHs, suggest that the stabilization observed for PaG6PDH could be a characteristic that distinguishes this and other G6PDHs that use NAD+ and NADP+ from those that use NADP+ only or preferentially, such as those found in eukaryotes. This characteristic could be related to the metabolic roles these enzymes play in the organisms to which they belong.

The effects of salt stress cause a diversion of basal metabolism in barley roots: possible different roles for glucose-6-phosphate dehydrogenase isoforms.

In this study the effects of salt stress and nitrogen assimilation have been investigated in roots of hydroponically-grown barley plants exposed to 150 mM NaCl, in presence or absence of ammonium as the sole nitrogen source. Salt stress determines a diversion of root metabolism towards the synthesis of osmolytes, such as glycine betaine and proline, and increased levels of reduced glutathione. The metabolic changes triggered by salt stress result in a decrease in both activities and protein abundance of key enzymes, namely GOGAT and PEP carboxylase, and in a slight increase in HSP70. These variations would enhance the requirement for reductants supplied by the OPPP, consistently with the observed increase in total G6PDH activity. The involvement and occurrence of the different G6PDH isoforms have been investigated, and the kinetic properties of partially purified cytosolic and plastidial G6PDHs determined. Bioinformatic analyses examining co-expression profiles of G6PDHs in Arabidopsis and barley corroborate the data presented. Moreover, the gene coding for the root P2-G6PDH isoform was fully sequenced; the biochemical properties of the corresponding protein were examined experimentally. The results are discussed in the light of the possible distinct roles and regulation of the different G6PDH isoforms during salt stress in barley roots.

Classification of Plasmodium falciparum glucose-6-phosphate dehydrogenase inhibitors by support vector machine.

Plasmodium falciparum glucose-6-phosphate dehydrogenase (PfG6PD) has been considered as a potential target for severe forms of anti-malaria therapy. In this study, several classification models were built to distinguish active and weakly active PfG6PD inhibitors by support vector machine method. Each molecule was initially represented by 1,044 molecular descriptors calculated by ADRIANA.Code. Correlation analysis and attribute selection methods in Weka were used to get the best reduced set of molecular descriptors, respectively. The best model (Model 2w) gave a prediction accuracy (Q) of 93.88 % and a Matthew's correlation coefficient (MCC) of 0.88 on the test set. Some properties such as [Formula: see text] atom charge, [Formula: see text] atom charge, and lone pair electronegativity-related descriptors are important for the interaction between the PfG6PD and the inhibitor.

G6PD--an old bottle with new wine.

The major role of glucose-6-phosphate dehydrogenase (G6PD) is to generate reduced nicotinamide adenine dinucleotide phosphate (NADPH), which is indispensable to reductive metabolism and maintenance of cellular redox homeostasis. Most advances in this field have been made in the pathophysiology of G6PD-deficient erythrocytes and the molecular characterization of different G6PD variants. Recently, numerous studies have shown the importance of G6PD in cell growth, development and disease progression.

Allozyme differentiation among nine populations of the corn borer (Ostrinia) in China.

To test the hypothesis of the migration of the corn borer, the allozymes of nine populations of the corn borer (Ostrinia) in China were checked using vertical-slab polyacrylamide gel electrophoresis. Eight loci of six allozymes were analyzed. The mean of the genetic identities among the nine populations calculated from the allele frequencies was 0.99068, much closer than that of other species and geographical populations. The mean (0.97955) of the genetic identities between the XJYN population (Ostrinia nubilalis Hübner, collected from Yining, Xinjiang Autonomous Region) and each of the other eight populations (O. furnacalis Guenée) was significantly smaller than that between the pairs of the eight populations (0.99386; t test, P < 0.01). Although the population XJYN clearly deviates from the other eight populations in the dendrogram, the relationship of the two species of corn borer was very close. It is possible that the speciation of corn borer may have resulted from single-gene substitutions.

[Identification of molecular variants of the enzyme glucose-6-phosphate dehydrogenase by the polymerase chain reaction technique]. / Identificación de variantes moleculares de la enzima glucosa-6-fosfato deshidrogenasa mediante la técnica de la reacción en cadena de la polimerasa.

BACKGROUND: An assessment of the usefulness of polymerase chain reaction (PCR) in the identification of the most frequent molecular variants of the glucose-6-phosphate dehydrogenase (G6PD) in Spain: G6PD A-, G6PD Mediterranean and G6PD Seattle through the screening of the mutations: 376 A-->G; 202 G-->A; 680 G-->T; 968 T-->C; 563 C-->T and 844 G-->C. METHODS: Three groups of patients have been studied: 1) males (40 cases); 2) relatives from the preceding group (31 cases: 7 males and 24 females), and 3) samples classified according to their fast electrophoretic mobility as G6PD A-(17 cases). The method used has been the PCR followed by digestion with specific restriction endonucleases. RESULTS: Group 1: 23 out of 40 samples (57%), were identified as G6PD Med563T variant (8 cases), G6PD A-376G/202A (13 cases) and G6PD Seattle844C (2 cases). Group 2: The study of relatives from 13 of the 23 identified samples allowed the study of additional 31 samples (7 males, 24 females): hemizygous G6PD Med563T (3 cases), heterozygous GdB/Gd Med563T (5 cases), hemizygous G6PD A-376G/202A (4 cases), heterozygous GdB/Gd A-376G/202A (11 cases), heterozygous GdB/Gd Seattle844C (1 case) and normal females (7 cases). Group 3: In all electrophoretically fast samples classified as G6PD A-was detected the 376 A-->G mutation (characteristic of G6PD A+). In 15 of these cases a second mutation was found at nucleotide 202 G-->A (G6PD A-376G/202A); and in two, at nucleotide 968 T-->C (G6PD A-376G/968C). CONCLUSIONS: The PCR method is fast and simple enough to allow the identification of known G6PD deficient variant, avoiding the need of its molecular characterization, which is more cumbersome and time consuming. In addition, the PCR is a very useful tool for demonstrating the carrier condition of G6PD deficiency in females with enzyme activity within normal range.

Definition of the mutations of G6PD Wayne, G6PD Viangchan, G6PD Jammu, and G6PD 'LeJeune'.

We report the nucleotide (nt) substitutions of four unrelated glucose-6-phosphate dehydrogenase (G6PD)-deficient males. Only the mutation of G6PD Wayne was unique. It was a nt 769 C----G substitution causing a deduced substitution of glycine for arginine at amino acid 257. This mutation is in a region in which G6PD mutations have previously been associated with chronic hemolytic anemia. The mutation of G6PD Jammu and G6PD Viangchan were identical: a G----A mutation at nucleotide 871, predicting a Val----Met substitution at amino acid 291. However, these two variants differ with respect to the 1311 polymorphism, suggesting that they may have arisen independently. Enzyme from a child with chronic hemolytic anemia, designated G6PD 'LeJeune', proved to be due to a G----T substitution at nt 637, a change identical with that in 3 unrelated patients who had been reported previously as having G6PD Gastonia, Minnesota and Marion. These findings support the suggestion that both polymorphic and sporadic G6PD deficiency mutations in unrelated persons with G6PD deficiency are often the same, even when thought to be distinct on the basis of biochemical characterization.

G6P-DH Santa Clara and G6P-DH Villa Clara: two new Cuban variants.

Two new glucose 6-phosphate dehydrogenase G6P-DH variants designated G6P-DH Santa Clara and G6P-DH Villa Clara were identified in a Cuban family. These variants belong to class III. Their electrophoretic and kinetic properties allow the conclusion that G6P-DH Santa Clara and G6P-DH Villa Clara are probably two new variants.

Effects of glucose-6-phosphate dehydrogenase deficiency upon sickle cell anemia.

We studied the interactions of the A- variety of glucose-6-phosphate dehydrogenase (G6PD) deficiency and sickle cell anemia (HbSS) to see if G6PD deficiency influenced laboratory and clinical features of HbSS. A total of 801 male patients over age 2 had G6PD electrophoresis on cellulose acetate membranes. Assays of both G6PD activity and hexokinase activity were then done on all samples that had an electrophoretic pattern other than the normal wild type (GdB). The collection of clinical data used a standardized protocol. Using cluster analyses we classified 10.4% males to be G6PD deficient, while 18.4% had the functionally normal GdA+ enzyme. The prevalence of G6PD deficiency did not change significantly when age was stratified by decade, suggesting little survival advantage or disadvantage of the combination of G6PD deficiency and HbSS. Compared to patients who were not G6PD deficient, there were no significant differences in the hemoglobin concentration, mean corpuscular volume, reticulocyte count, bilirubin, or SGOT level in patients with HbSS who had G6PD deficiency. The incidence of painful episodes, sepsis, or acute anemic episodes was similar in both groups. Our results are consistent with recent studies of smaller numbers of patients that have found little influence of G6PD deficiency upon HbSS. Specifically, we found no evidence that G6PD enhanced the severity of hemolysis or increased the incidence of acute anemic episodes or sepsis in HbSS.

Two new variants of glucose-6-phosphate dehydrogenase associated with hereditary non-spherocytic hemolytic anemia: G6PD Wayne and G6PD Huron.

Two new deficient variants of glucose-6-phosphate dehydrogenase (G6PD) causing hereditary nonspherocytic hemolytic anemia (HNSHA) are described. Both of these are unique and they have been named G6PD Wayne and G6PD Huron. Patients with G6PD Wayne underwent splenectomy and no objective improvement was noted. The patients with G6PD Huron were under medical observation for a considerable period of time without the diagnosis of G6PD deficiency being entertained because the family was of Northern European origin. Since sporadic variants of G6PD causing HNSHA show no special racial predilection, the diagnosis of G6PD deficiency should always be considered in patients with this syndrome.

Evidence for a multistep pathogenesis of chronic myelogenous leukemia.

To study the relationship of the Philadelphia chromosome (Ph1) to the pathogenesis of chronic myelogenous leukemia, multiple B-lymphoid cell lines were established from a patient with Ph1-positive leukemia who was heterozygous for the X-chromosome-linked enzyme glucose-6-phosphate dehydrogenase. Both A and B types of enzyme were found in a 1:1 proportion in normal tissues, but 45 of 63 (71%) Ph1-negative B-lymphoid cells lines derived from this patient showed only the single glucose-6-phosphate dehydrogenase (type B) found in the Ph1-positive leukemic clone. Furthermore, 8 of 33 analyzable lines with B-type enzyme had chromosomal aberrations compared to 0 of 14 lines with A-type glucose-6-phosphate dehydrogenase. These results provide evidence for the suggestion that some cells of the abnormal clone do not express the Ph1 abnormality. Thus, acquisition of Ph1 may not be a sufficient cause for the disease. It is possible that at least two steps are involved in the pathogenesis of Ph1-positive chronic myelogenous leukemia, one causing abnormal proliferation of a clone of pluripotent hematopoietic stem cells and the other inducing Ph1 in descendants of these progenitors.

Glucose-6-phosphate dehydrogenase deficiency and blood transfusion.

Seven White American male blood donors with Italian surnames were found to have red cell glucose-6-phosphate dehydrogenase (G-6-PD) deficiency among 1,285 with Greek or Italian surnames screened. Five different genetic variants were found; G-6-PDs Mediterranean (2), "Athens-like" (2), San Juan, Columbus and "Canton-like". Clinical evaluation of 23 patients who received 24 units of G-6-PD-deficient blood (G-6-PD A-) failed to reveal any deleterious effects. Screening of Black donors for G-6-PD deficiency is believed unnecessary; further data are needed before a recommendation can be made concerning screening for non-Black donors.