HbS-Savaria: The Anti-polymerization Effect of a Single Mutation in Human α-chains

Recombinant α-Savaria globin (α^S49R) was assembled with β^S chains by the alloplex intermediate pathway to generate tetrameric rHbS-Sarvaria (α₂^S49Rβ₂^E6V) that exhibited normal O₂ affinity and co-operatively at pH 7.4. Allosteric effectors, 2,3-DPG, L35, and NaCl increased O₂ affinity by 15%. Bohr effects were similar for rHbS-Savaria and HbS (0.38 ± 0.025 vs. 0.46 ± 0.03, respectively). The C_SAT of HbS increased from 16.7 ± 0.8 to 27.0 ± 1.0 g/dL. Co-polymerization demonstrated inhibition predominantly by the Cis-dimer. Molecular modeling indicated that the positive charge at α-49 generated a strong anion-binding site and reduced flexibility of the CD-region by restricting movement in the E and F helices. The molecular distance between Arg-49 and Asn-78 in the neighboring double strand decreased, and electrostatic repulsion between the inter-double strands increased, resulting in inhibition of polymerization. The Savaria mutation may be useful for the design of super-inhibitory α-chains and gene therapy of sickle cell anemia.     

Molecular evolution of hemoglobins of antarctic fishes (Notothenioidei)

Amino acid sequences of α- and β-chains of human hemoglobin and of hemoglobins of coelacanth and 24 teleost fish species, including 11 antarctic and two temperate Notothenioidei, were analyzed using maximum parsimony. Trees were derived for the α- and β-chains separately and for tandemly arranged sequences, using the human and coelacanth sequences as outgroups in all analyses. The topologies of the trees of the α-and β-chains are highly congruent and indicate a specific pattern of gene duplications and gene expression of teleost hemoglobins which has not yet been investigated into more detail. The Notothenioid fish generally contain a single major hemoglobin and often a second minor component. The α- and β-chains of the major components form a monophyletic group in all investigated trees, with the nonantarctic Pseudaphritis as their sister taxon. The minor chains also are a monophyletic group and form an unresolved cluster with the major chains and the hemoglobins of tuna and red gurnard. The Notothenioid families Nototheniidae and Bathydraconidae appear to be paraphyletic. Received: 26 March 1997 / Accepted: 7 May 1997     

Genomic organization and gene expression of the multiple globins in Atlantic cod: conservation of globin-flanking genes in chordates infers the origin of the vertebrate globin clusters

Background  

The vertebrate globin genes encoding the α- and β-subunits of the tetrameric hemoglobins are clustered at two unlinked loci. The highly conserved linear order of the genes flanking the hemoglobins provides a strong anchor for inferring common ancestry of the globin clusters. In fish, the number of α-β-linked globin genes varies considerably between different sublineages and seems to be related to prevailing physico-chemical conditions. Draft sequences of the Atlantic cod genome enabled us to determine the genomic organization of the globin repertoire in this marine species that copes with fluctuating environments of the temperate and Arctic regions.     

Origin and evolution of the sulawesi macaques 1. Electrophoretic analysis of hemoglobins

The monkeys on the island of Sulawesi (Celebes), Indonesia, comprise seven species ofMacaca, that isM. maura, M. tonkeana, M. hecki, M. nigrescens, M. nigra, M. ochreata, andM. brunnescens. Hemoglobins from 248 individuals of these seven species were analyzed by isoelectric focusing electrophoresis (IEFE) and by starch gel electrophoresis in the presence of urea (USGE). Eighteen phenotypes consisting of eight molecular types were identified by IEFE analysis. The speciestonkeana inhabiting the central part of the island revealed 11 phenotypes, while peripheral species such asnigrescens andbrunnescens carried only 3 and 2 phenotypes, respectively. On USGE, three α chains and three β chains were identified and named α1, α2, and α6, and β1, β3, and β5, respectively. The α1 chain has the same mobility as the α chains of other macaques, while the α2 chain is less positively charged than α1, and α6 is the least positive among these α chains. The α2 chain is widely distributed in the Sulawesi macaques as the major component. Four species,ochreata, tonkeana, maura, andnigrescens, carried the α1 and α6 chains as minor components. The electrophoretic mobility of β1 was the same as that of other macaques, while β3 and β5 were more positively charged and less positively charged than β1, respectively. All of the Sulawesi species had β3 in high or low gene frequencies and inmaura, tonkeana, andbrunnescens, this type was most abundant. β5 chain existed in the species of the northern peninsula, as the major type. The subordinate type was β3 innigra andnigrescens and β1 inhecki. On the other hand, β1 was most frequently observed inochreata.     

Population genetic analysis of the haemoglobins of the black-chinned tilapia

Three highly heterogeneous haemoglobin phenotypes, each composed of 22 different haemoglobin components, were identified among 17 West African populations of Sarotherodon melanotheron . Natural populations from (1) Senegal, (2) Ivory Coast/Ghana/Togo/Benin, and (3) Congo were distinguished. The heterogeneity and specificity of these respiratory pigments was based on genetic variations at the globin chain coding loci. In total, five different α-chains and four different β-chains were detected by acidic urea polyacrylamide gel electrophoresis (PAGE). Combinations of α-chains were characteristic for populations in (1) Senegal, (2) Ivory Coast, (3) Ghana/Togo/Benin, and (4) Congo. Pronounced variations at the β-globin chain cluster were found by acidic urea triton PAGE. Cladistic analyses of the globin chain characteristics confirmed the validity of the following taxonomic units previously ranked as sub-species: (1) populations from Ivory Coast, Ghana, Togo and Benin belong to the sub-species S. m. melanotheron ; (2) populations from Senegal form genetically a separate cluster representing the sub-species S. m. heudelotii ; (3) the Congo population, morphologically considered to represent the sub-species S. m. nigripinnis , forms another distinct unit; but there was no evidence of S. m. paludinosus within the samples from Senegal.     

Structural and functional characterization of <Emphasis Type="Italic">Delphinus delphis</Emphasis> hemoglobin system

Structural analysis of the hemoglobin (Hb) system of Delphinus delphis revealed a high globin multiplicity: HPLC–electrospray ionization-mass spectrometry (ESI-MS) analysis evidenced three major β (β1 16,022 Da, β2 16,036 Da, β3 16,036 Da, labeled according to their progressive elution times) and two major α globins (α1 15,345 Da, α2 15,329 Da). ESI-tandem mass and nucleotide sequence analyses showed that β2 globin differs from β1 for the substitution Val126 → Leu, while β3 globin differs from β2 for the isobaric substitution Lys65 → Gln. The α2 globin differs from the α1 for the substitution Ser15 → Ala. Anion-exchange chromatography allowed the separation of two Hb fractions and HPLC–ESI-MS analysis revealed that the fraction with higher pI (HbI) contained β1, β2 and both the α globins, and the fraction with lower pI (HbII) contained β3 and both the α globins. Both D. delphis Hb fractions displayed a lower intrinsic oxygen affinity, a decreased effect of 2,3-BPG and a reduced cooperativity with respect to human HbA₀, with HbII showing the more pronounced differences. With respect to HbA₀, either the substitution Proβ5 → Gly or the Proβ5 → Ala is present in all the cetacean β globins sequenced so far, and it has been hypothesized that position 5 of β globins may have a role in the interaction with 2,3-BPG. Regarding the particularly lowered cooperativity of HbII, it is interesting to observe that the variant human HbA, characterized by the substitution Lysβ65 → Gln (HbJ-Cairo) has a decreased cooperativity with respect to HbA₀.     

Linking conformation change to hemoglobin activation via chain-selective time-resolved resonance Raman spectroscopy of protoheme/mesoheme hybrids

Time-resolved resonance Raman (RR) spectra are reported for hemoglobin (Hb) tetramers, in which the α and β chains are selectively substituted with mesoheme. The Soret absorption band shift in mesoheme relative to protoheme permits chain-selective recording of heme RR spectra. The evolution of these spectra following HbCO photolysis shows that the geminate recombination rates and the yields are the same for the two chains, consistent with recent results on ¹⁵N-heme isotopomer hybrids. The spectra also reveal systematic shifts in the deoxyheme ν ₄ and ν _Fe–His RR bands, which are anticorrelated. These shifts are resolved for the successive intermediates in the protein structure, which have previously been determined from time-resolved UV RR spectra. Both chains show Fe–His bond compression in the immediate photoproduct, which relaxes during the formation of the first intermediate, R_deoxy (0.07 μs), in which the proximal F-helix is proposed to move away from the heme. Subsequently, the Fe–His bond weakens, more so for the α chains than for the β chains. The weakening is gradual for the β chains, but is abrupt for the α chains, coinciding with completion of the R–T quaternary transition, at 20 μs. Since the transition from fast- to slow-rebinding Hb also occurs at 20 μs, the drop in the α chain ν _Fe–His supports the localization of ligation restraint to tension in the Fe–His bond, at least in the α chains. The mechanism is more complex in the β chains.     

Increases in α-mannosidase activity in the arbuscular mycorrhizal symbiosis of Allium schoenoprasum

 Mycorrhizal and nonmycorrhizal roots of Allium schoenoprasum were tested for activities of α-mannosidase, β-glucosidase and arabinosidase. Mannosidase activity was higher by a factor of two in mycorrhizal than in nonmycorrhizal root extracts. The apparent molecular weight of the enzyme was 152 kDa and its K_M was 1.25 mM in colonized roots and 1.85 mM in uncolonized roots. α-Mannosidase activity was further characterized by an acid pH optimum and Zn²⁺ dependency. No significant differences could be found between mycorrhizal and nonmycorrhizal roots for β-glucosidase and arabinosidase activities. Accepted: 28 August 1995     

Embryonic β-globin in the non-Antarctic notothenioid fish Cottoperca gobio (Bovichtidae)

Haemoglobins are sensitive to temperature and their properties mirror the thermal conditions encountered by species during their evolutionary histories. This paper provides data on molecular phylogeny of the haemoglobin chains of Cottoperca gobio, a notothenioid fish of sub-Antarctic latitudes, belonging to the basal family Bovichtidae. Unlike most Antarctic notothenioids, C. gobio has two major haemoglobins sharing the β chain. In the molecular phylogenetic analysis, the β chain is included in the clade of the “embryonic” or minor Antarctic globins. Although, in the majority of notothenioids, “embryonic” (minor) α and β globins are expressed in traces or small amounts in the adult stage, in C. gobio the present analysis supports the occurrence of a complete “switch” to exclusive expression of the embryonic β-globin gene in adult fish. The α and β chains sequences have been used to expand our knowledge of the evolution of notothenioid haemoglobins.The protein sequence data reported in this paper will appear in the UniProt Knowledge base under the accession number: P84652 (β chain), P84653 (α ¹ chain).     

Developmental pattern and molecular identification of globin chains in Xenopus laevis

Summary High-resolution electrophoresis of larval and adult hemoglobins of Xenopus laevis reveals stage-specific differences in the number and mobility of the globin chains. To establish the relationship between the globin chains and the previously described globin genes, the corresponding mRNAs were hybrid-selected from total erythroblast RNA by representative cDNA clones, and translated in vitro. Electrophoretic separation of the translation products allowed identification of a major and a minor -globin chain in the larval and adult stages. This also holds for the adult -chains, however in the larval stage a difference in abundance is only detectable in the -mRNAs, but not in the translation products, because they comigrate. The fact that major and minor globin chains can be assigned to genes, which are located in two clusters, suggests that the related genes are expressed coordinately, but at different levels. Analysis of the globin patterns during development reveals that transition from the larval to the adult globin chains coincides with metamorphosis. Moreover, there is evidence of two globin chains that are only expressed in early larval stages and hence might be related to additional larval -globin genes of as yet unknown genomic location.     

Direct analysis of α- and β-chains of hemoglobins from mammalian blood samples by nanoESI mass spectrometry during in-capillary proteolytic digestion

α- and β-chains of hemoglobins derived from several species were analyzed directly from diluted blood samples by simultaneous in-capillary proteolytic digestion and nanoESI MS and MS/MS analysis. Starting from fresh or frozen and thawed blood samples, sequence coverages of >80% were usually obtained. Only 2 h after resuspension of a dried blood spot, human origin could be demonstrated from data obtained by in-capillary tryptic digestion, nanoESI mass spectrometric analysis, and data base search. A fast and facile differentiation of closely related species by hemoglobin-derived proteolytic “marker peptides” was demonstrated for Asian (Elephas maximus) and African elephants (Loxodonta africana). Finally, amino acid sequences deduced from collision-induced dissociation experiments during in-capillary proteolytic digestion of the corresponding blood samples allowed de novo sequencing of previously unknown sequences of hemoglobin chains of the Patagonian cavy (Dolichotum patagona) and the Persian gazelle (Gazella subgutturosa subgutturosa). 100% of the α-chain sequences and more than 85% of the β-chain sequences were covered for both the species. Additionally, sequence data derived from tandem MS experiments obtained with the Q-Tof analyzer were confirmed by high resolution Fourier-transform ion cyclotron resonance mass spectrometric experiments. Accurate protein mass determination of the intact hemoglobin chains directly from the corresponding blood samples by use of a Fourier-transform ion cyclotron resonance mass spectrometer corroborated the deduced sequences of the respective α-chains. The present study demonstrates that in-capillary digestion allows fast characterization and/or sequencing of hemoglobin chains directly from blood samples.     

Evolutionary trends in the hemoglobins of murine animals

The evolutionary origin of murine line based on a phylogenetic tree made on sequence data of ∞-and β-hemoglobin chains, followed by the diversity spectrum of hemoglobin genes in two wild species of murine rodents:Rattus rattus rufescens (house rat) andBandicota indica (bandicoot rat) has been reported. Each house rat contains six hemoglobin types involving two ∞-and three β-chains, which suggests a probable gene duplication at the oc chain locus and a gene triplication at the β-chain locus. Each bandicoot rat contains one ∞-and two β-chains suggesting a probable gene duplication at the β-chain locus. Peptide pattern analysis of the polypeptide chains of these murine hemoglobins further indicates that intraspecies differences among duplicated chains of the same kind are less than interspecies differences among corresponding ∞-and β-chains.     

Yeast holoenzyme of protein kinase CK2 requires both β and β′ regulatory subunits for its activity

Protein kinase CK2 is a highly conserved Ser/Thr protein kinase that is ubiquitous among eucaryotic organisms and appears to play an important role in many cellular functions. This enzyme in yeast has a tetrameric structure composed of two catalytic (α and/or α′) subunits and two regulatory β and β′ subunits. Previously, we have reported isolation from yeast cells four active forms of CK2, composed of αα′ββ′, α₂ββ′, α′₂ββ′ and a free α′-catalytic subunit. Now, we report that in Saccharomyces cerevisiae CK2 holoenzyme regulatory β subunit cannot substitute other β′ subunit and only both of them can form fully active enzymatic unit. We have examined the subunit composition of tetrameric complexes of yeast CK2 by transformation of yeast strains containing single deletion of the β or β′ regulatory subunits with vectors carrying lacking CKB1 or CKB2 genes. CK2 holoenzyme activity was restored only in cases when both of them were present in the cell. Additional, co-immunoprecypitation experiments show that polyadenylation factor Fip1 interacts with catalytic α subunits of CK2 and interaction with beta subunits in the holoenzyme decreases CK2 activity towards this protein substrate. These data may help to elucidate the role of yeast protein kinase CK2β/β′ subunits in the regulation of holoenzyme assembly and phosphotransferase activity.     

Low-specificity l-threonine aldolase of Pseudomonas sp. NCIMB 10558: purification, characterization and its application to β-hydroxy-α-amino acid synthesis

Low-specificity l-threonine aldolase, catalyzing the reversible cleavage/condensation reaction between l-threonine/l-allo-threonine and glycine plus acetaldehyde, was purified to homogeneity from Pseudomonas sp. NCIMB 10558. The enzyme has an apparent molecular mass of approximately 145 kDa and consists of four identical subunits with a molecular mass of 38 kDa. The enzyme, requiring pyridoxal- 5′-phosphate as a coenzyme, is strictly l-specific at the α position, whereas it can not distinguish between threo and erythro forms at the β position. Besides the reversible cleavage/condensation of threonine, the enzyme also catalyzes the reversible interconversion between glycine plus various aldehydes and l-β-hydroxy-α-amino acids, including l-β-(3,4-dihydroxyphenyl)serine, l-β-(3,4-met‐hylenedioxyphenyl)serine and l-β-phenylserine, providing a new route for the industrial production of these important amino acids. Received: 10 November 1997 / Received revision: 7 January 1998 / Accepted 30 January 1998     

Extraction and purification of an unusual phycoerythrin in a terrestrial desiccation tolerant cyanobacterium <Emphasis Type="BoldItalic">Lyngbya arboricola</Emphasis>

Presence and stability of an unusual phycoerythrin (PE) characteristically similar to R-PE are described in a terrestrial, desiccation-tolerant cyanobacterium, Lyngbya arboricola. Extraction and purification of the PE by using acetone precipitation, gel filtration and ion-exchange chromatography resulted in achieving a purity index (A₅₆₀/A₂₈₀) of up to 5.2. SDS-PAGE of the PE showed presence of 18 kDa, 20 kDa and 32 kDa bands corresponding to α, β and γ subunits of R-PE without any other contaminating phycobiliproteins (PBPs). The absorption spectrum of the PE was distinguished by two major peaks at 499 and 559 nm. The maximum fluorescence emission at room temperature was 578 nm. Spectroscopic and electrophoresis characteristics of PE in the dry mats on storage at 25 ± 1°C over silica gel for 2 years remained almost unaffected. Quantitatively, storage stability of the PE was in the order of dry mats > lyophilized > liquid state and the impact of temperature on loss of PE was in the order of 25°C > −20°C > 4°C. The relevance of L. arboricola for production of stable unusual PE is discussed.     

Differences among plant species in cuticular permeabilities and solute mobilities are not caused by differential size selectivities

Solute mobilities in cuticular membranes of six species (Hedera helix, Malus domestica, Populus alba, Pyrus communis, Stephanotis floribunda, Strophantus gratus) were measured using plant hormones, growth regulators and other organic model compounds varying in molar volumes from 99 to 349 mL · mol⁻¹ The dependence of mobilities (k*) on molar volume (V _x ) was exponential and could be described with equations of the type log k*=log k*⁰−^′ V _x . The y-intercepts (log k*⁰) represent mobilities of a hypothetical solute of zero molar volume. The parameter β′ is a measure of size selectivity of cuticular membranes and no differences among the six species were observed. At 25 °C the average β′ was 0.0095 mol · mL⁻¹. Solute mobility decreased by about a factor of 8.9 when molar volume increased by 100 mL · mol⁻¹ and the mobility of a compound with V _x  = 100 mL · mol⁻¹ was about 700-fold higher than the mobility of a compound with V _x  = 400 mL · mol⁻¹. Size selectivity decreased with increasing temperatures and for Strophantusβ′-values of 1.6 × 10⁻² to 8.0 × 10^-4 mol · mL⁻¹ were obtained for 10 and 30 °C, respectively. The-intercepts (log k*⁰) differed among plant species by 3 orders of magnitude and since size selectivity was the same for all species, solute mobilities for solutes having zero molar volumes were the sole cause for differences among species in solute mobilities and permeabilities. We argue that these differences in k*⁰ are related to tortuosity of the diffusion path. These results were used to derive an equation which predicts rates of cuticular penetration on the basis of k*⁰, the average size selectivity of 9.5 × 10⁻³ mol · mL⁻¹ and the driving forces of penetration. Received: 25 November 1997 / Accepted: 9 March 1998     

Light-regulated localization of the beta-subunit of Gq-type G-protein in the crayfish photoreceptors

In crayfish photoreceptor cells, Gq-type G-protein plays a central role in the phototransduction pathway, and the translocation of Gqα has been proposed as one of the molecular mechanisms to control photoreceptor sensitivity. We here investigated β subunit of Gq and its localization profiles under various light conditions in the crayfish photoreceptor cells to understand the functional characteristic of visual Gq in the phototransduction pathway. An immunoprecipitation experiment was performed using an anti-Gqα antibody and a thiol-cleavable crosslinker. A 39 kDa protein was co-immunoprecipitated with Gqα, but not by irradiation, in the presence of GTPγS. The partial amino acid sequence of the 39 kDa protein was similar to Gβe in Drosophila photoreceptors, indicating that the crayfish Gβ which combines with Gqα is a Gβe homologue. Immunohistochemical and immunoblot analyses revealed that the amount of the Gβ decreased in the rhabdomeric membranes and increased in the cytoplasm in the light, compared with that in the dark. The profile of the translocation was similar to that reported for Gqα. Since both α and βγ subunits are necessary for G-proteins to be activated by rhodopsin in the rhabdom, the light-modulated translocation of a Gβe homologue possibly controls the amount of Gq which can be activated by light-stimulated rhodopsin. Accepted: 27 June 1998     

Pyranose 2-oxidase from Phanerochaete chrysosporium– further biochemical characterisation

Pyranose 2-oxidase (P2O) was purified 43-fold to apparent homogeneity from the basidiomycete Phanerochaete chrysosporium using liquid chromatography on phenyl Sepharose, Mono Q (twice) and phenyl Superose. The native enzyme has a molecular mass of about 250 kDa (based on native PAGE) and is composed of four identical subunits of 65 kDa. It contains three isoforms of isoelectric point (pI) 5.0, 5.05 and 5.15 and does not appear to be a glycoprotein. P2O is optimally stable at pH 8.0 and up to 60 °C. It is active over a broad pH range (5.0–9.0) with maximum activity at pH 8.0–8.5 and at 55 °C, and a broad substrate specificity. d-Glucose is the preferred substrate, but 1-β-aurothioglucose, 6-deoxy-d-glucose, l-sorbose, d-xylose, 5-thioglucose, d-glucono-1,5-lactone, maltose and 2-deoxy-d-glucose are also oxidised at relatively high rates. A Ping Pong Bi Bi mechanism was demonstrated for the P2O reaction at pH 8.0, with a catalytic constant (k _cat) of 111.0 s⁻¹ and an affinity constant (K _m) of 1.43 mM for d-glucose and 83.2 μM for oxygen. Whereas the steady-state kinetics for glucose oxidation were unaffected by the medium at pH ≥ 7.0, at low pH both pH and buffer composition affected the P2O kinetics with the k _cat/K _m value decreasing with decreasing pH. The greatest effect was observed in acetate buffer (0.1 M, pH 4.5), where the k _cat decreased to 60.9 s⁻¹ and the K _m increased to 240 mM. The activity of P2O was completely inhibited by 10 mM HgCl₂, AgNO₃ and ZnCl₂, and 50% by lead acetate, CuCl₂ and MnCl₂. Received: 28 August 1996 / Received revision: 25 November 1996 / Accepted: 29 November 1996     

Pair-wise interactions of polymerization inhibitory contact site mutations of hemoglobin-S

The linkage of pair-wise interactions of contact site mutations of HbS has been studied using Le Lamentin [His-20 (α)→Gln], Hoshida [Glu-43 (β)→Gln] and α₂β₂^T87Q mutations as the prototype of three distinct classes of contact sites of deoxy HbS fiber. Binary mixture experiments established that β^A-chain with the Thr-87 (β)→Gln mutation is as potent as the γ-chain of HbF (α₂γ₂) in inhibiting polymerization. On combining the influence of Le Lamentin mutation with that of β₂^T87Q mutations; the net influence is only partial additivity. On the other hand, in binary mixture studies, combined influence of Hoshida mutation with that of β₂^T87Q mutations is synergistic. Besides, a significant level of synergistic complementation is also seen when the Le Lamentin and Hoshida mutations are combined in HbS (symmetrical tetramers). Le Lamentin and Hoshida mutation introduced into the cis-dimer of the asymmetric hybrid tetramer completely neutralizes the Val-6 (β) dependent polymerization. Accordingly, we propose that combining the perturbation of intra-double strand contact site with that of an inter-double strand contact site exhibit synergy when they are present in two different chains of the αβ dimer. A comparison of the present results with that of the earlier studies suggest that when the two contact site perturbations are from the same sub-unit of the αβ dimer only partial additivity is observed. The map of interaction linkage of the contact site mutations exposes new strategies in the design of novel anti-sickling Hbs for the gene therapy of sickle cell disease.     

Carnivora: the primary structure of hemoglobin from adult coati (Nasua nasua rufa, Procyonidae)

The complete primary structure of the hemoglobin from the adult coati (Nasua nasua rufa) is presented. The erythrocytes contain one hemoglobin component and two globin chains. The isolation of globin chains was achieved by reversed-phase HPLC on a column of Nucleosil-C4. The primary structure of globin chains and tryptic peptides was determined in liquid- and gas-phase sequenators. The sequence of the and -chains of coati compared with those of other Carnivora species. Results are discussed with respect to structural variations and the phylogenetic relationship.Deceased on May 27, 1989.