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PubMed1990

The effects of amino acid substitution at position E7 (residue 64) on the kinetics of ligand binding to sperm whale myoglobin.

Association and dissociation rate constants were measured for O2, CO, and alkyl isocyanide binding to a set of genetically engineered sperm whale myoglobins with site-specific mutations at residue 64 (the E7 helical position). Native His was replaced by Gly, Val, Leu, Met, Phe, Gln, Arg, and Asp using the synthetic gene and expression system developed by Springer and Sligar (Springer, B. A., and Sligar, S. G. (1987) Proc. Natl. Acad. Sci. U.S.A. 84, 8961-8965). The His64----Gly substitution produced a sterically unhindered myoglobin that exhibited ligand binding parameters similar to those of chelated protoheme suspended in soap micelles. The order of the association rate constants for isocyanide binding to the mutant myoglobins was Gly64 (approximately 10(7) M-1 s-1) much greater than Val64 approximately Leu64 (approximately 10(6) M-1 s-1) greater than Met64 greater than Phe64 approximately His64 approximately Gln64 (10(5)-10(3) M-1 s-1) and indicates that the barrier to isocyanide entry into the distal pocket is primarily steric in nature. The bimolecular rates of methyl, ethyl, n-propyl, and n-butyl isocyanide binding to the His64----Arg and His64----Asp mutants were abnormally high (1-5 x 10(6) M-1 s-1), suggesting that Arg64 and Asp64 adopt conformations with the charged side chains pointing out toward the solvent creating a less hindered pathway for ligand binding. In contrast to the isocyanide data, the association rate constants for O2 and CO binding exhibited little dependence on the size of the E7 side chain. The values for all the mutants except His64----Gln approached or were larger than those for chelated model heme (i.e. approximately 1 x 10(8) M-1 s-1 for O2 and approximately 1 x 10(7) M-1 s-1 for CO), whereas the corresponding rate parameters for myoglobin containing either Gln64 or His64 were 5- to 10-fold smaller. This result suggests that a major kinetic barrier for O2 and CO binding to native myoglobin may involve disruption of polar interactions between His64 and water molecules found in the distal pocket of deoxymyoglobin. Finally, the rate and equilibrium parameters for O2 and CO binding to the His64----Gln, His64----Val, and His64----Leu mutants were compared to those reported previously for Asian elephant myoglobin (Gln-E7), Aplysia limacina myoglobin (Val-E7), and monomeric Hb II from Glycera dibranchiata (Leu-E7).

Amino Acids↗
PubMed1990

Lactate does facilitate oxygen unloading from the hemoglobin of the whale, Balaenoptera acutorostrata, after diving.

The present study reports on a specific effect of lactate on the oxygen binding properties of the hemoglobin from the whale, Balaenontera acutorostrata. In fact 0.1 mM lactate may increase the amount of oxygen unloaded to the tissues as much as 30%. Under these conditions the Bohr shift, of the magnitude of about -1, does not alter the oxygen affinity, but plays an important role in the isohydric transport of carbon dioxide.

Animals↗
PubMed1990

[Three-dimensional structure of the lipotropic active fragment of sea whale somatotropin].

Using semiempirical conformational analysis method, the spatial structure and conformational properties of the sea-whale somatotropin lipotropic action were investigated. The calculations were based on the fragmental analysis using non-valent, electrostatic interactions, torsional barriers and hydrogen bonds. The computer data suggest that this molecule can exist only in several low energy conformational states. The experimental results can be used for the analysis of structural-and-functional relationships.

Amino Acid Sequence↗
PubMed1978

The effect of evolution on homologous proteins: a comparison between the chromophore microenvironments of Italian water buffalo (Bos bubalus, L.) and sperm whale apomyoglobin.

The perturbing effect of guanidium hydrochloride and pH on the molecular structure of water buffalo apomyoglobin has been investigated by circular dichroism in the far and near ultraviolet and by fluorescence. In the wavelength region between 320 and 260 nm the circular dichroic spectrum of the globin is highly structured and the contributions of the aromatic chromophores have been resolved. Buffalo apomyoglobin undergoes a structural transition at neutral pH which involves elements of the secondary and tertiary structure, as indicated by changes of dichroic activity of the peptide and aromatic chromophores and the fluorescence of the two tryptophanyl residues. The possibility of charge-transfer complex between indole and imidazole is discussed. A major structural transition with abrupt unfolding takes place in the pH region between 5.6 and 4.3. Below pH 4.3 the peptide helical residues, which survive the acid transition, appear to be resistent to further acidification to pH 2.0 while tryptophanyl emission is quenched and shifted to longer wavelengths. A structural transition occurs also in alkali above pH 10, which has been detected by the same techniques. The relationships between buffalo and sperm whale apomyoglobin are discussed.

Animals↗
PubMedDate not supplied

T-cell antigenic peptides from sperm whale myoglobin fold as amphipathic helices: a possible determinant for immunodominance?

Little is known about the requirements for immunodominance in a T-cell immune response. It has been speculated that after a foreign protein has undergone proteolytic processing, resulting peptides that can take on structures favorable for binding to histocompatibility proteins and for recognition by the T-cell receptor are immunodominant. DeLisi and Berzofsky (25) have proposed that the ability of a peptide fragment to fold as an amphipathic alpha-helix may increase the likelihood of its immunodominance. In an effort to understand how structure and immunodominance might be correlated, we have studied the biophysical properties of a series of peptides from sperm whale myoglobin (SWMb) which have already been characterized with respect to activation of T-cell clones from mice immunized against the whole protein. Our results suggest that peptides corresponding to immunodominant T-cell antigenic sites from SWMb tend to fold as amphipathic alpha-helices in structure-promoting and interfacial environments. Peptides with the sequences 132-146 and 102-118 were chosen for the study because they were found to be immunodominant for myoglobin-specific T cells (8) and were predicted to form amphipathic alpha-helices based on their residue distribution. Likewise, peptides with the sequences 93-102 and 115-130, which were predicted not to favor this conformation, were used as controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1989

Morphogenesis of the digestive tract in the fetuses of the southern minke whale, Balaenoptera acutorostrata.

Gross and histological observations on the digestive tract in 15 fetuses of the southern minke whale (Balaenoptera acutorostrata) with C.R.L. from 37.2 to 1,940mm revealed that the fetal stomach formation in this species resembled that of the ruminant, i.e., the compartment 1 arose from the stomach bud, but not from the esophagus to form the forestomach. The differentiated gastric glands, the parietal cells, were detected in fetuses with more than 213.0mm C.R.L. The circular folds resembling intestinal haustra like circular folds without tenia were detected on the cecum in fetuses with more than 650mm C.R.L. and less than 1,070mm C.R.L. The similar structure was seen in large intestine in fetuses with more than 650mm C.R.L.

Animals↗
PubMed1978

Acid and alkaline forms of the higher oxidation state of kangaroo, horse, and sperm whale myoglobin.

Myoglobin(IV), the derivative of myoglobin at the formal oxidation state IV, prepared from kangaroo (Megaleia rufa), horse, or sperm whale myoglobin, when cooled to liquid nitrogen temperature, assumes acid and alkaline forms with different optical spectra. The essential features of the optical spectra of the acid forms are the same as those of leghemoglobin(IV) and are very similar to those of optical spectra of the red higher oxidation states of catalases and peroxidases. This shows that the configuration of the heme iron is the same throughout these compounds. That configuration is believed to be Fe(IV) in a porphyrin environment. The optical spectra of alkaline mammalian myoglobin(IV), like that of alkaline leghemoglobin(IV), resemble those of the alkaline low spin ferric proteins. Kangaroo myoglobin(IV) may be prepared by reaction of ferrous myoglobin with hydrogen peroxide. The acid forms of myoglobin(IV) are conveniently prepared by cooling solutions in borate buffers, initially pH 8.3, to liquid nitrogen temperature. At this temperature borate buffers become acidic.

Animals↗
PubMed1978

Comparison of influenza viruses isolated from man and from whales.

Four isolates of influenza virus strains from Moscow and Habarovsk that caused outbreaks of influenza in November and December 1977 in several cities of the USSR were studied and their haemagglutinins and neuraminidases were compared with those of other human and animal influenza viruses including A/whale/Pacific Ocean/76. In H1 tests these isolates, designated A/USSR/77, reacted with immune serum against A/FM/1/47 (H1N1) to the homologous titre, and with antiserum against A/whale/PO/19/76 virus to 1/8 of the homologous titre. In neuraminidase inhibition tests all A/USSR/77 isolates showed the presence of human N1 type neuraminidase, more closely related to A/sw/New Jersey/76 (Hsw1N1) than to A/FM/1/47 (H1N1) virus. The haemagglutinin of A/whale/Pacific Ocean/19/76 virus occupies an intermediate position between H0 and H1, but its neuraminidase is close to Nav2. The virus from whales multiplies better at low (28 degrees C) and at high (40 degrees C) temperatures than do the viruses of human origin that were tested.

Adult↗
PubMedDate not supplied

[Isolation and properties of enzyme preparations from the whale pancreas].

A simple and convenient technique was developed for isolation of the proteolytic enzyme complexes from the whale (Balaenoptera) pancreas. The proposed techniques enables the proteolytic complexes to be obtained with the protein yield 2.6 times higher than the classical procedure. The proteolytic activity increased 3.2 times (casein as a substrate), esterase activities, 1.4 times (N-benzoyl-L-tyrosine methyl ester as a substrate) and 1.2 times (N-alpha-benzoyl-L-arginine ethyl ester as a substrate). Soybean and barley trypsin inhibitors and ovomycoid in free and immobilized state inhibit the esterase activities of the proteolytic complexes. An additional purification of the proteolytic complexes was carried out using the affinity sorbent Soybean trypsin inhibitor--Sepharose 4B. The molecular weight of the enzymes determined by means of PAAG electrophoresis was found to be 20 000-20 500. The hydrolysis of some synthetic substrates by the proteolytic enzyme complexes obtained according to the proposed techniques was being studied.

Animals↗
PubMed1986

[Morphogenesis of the highly specialized nasal skull in the sperm whale (Physeter macrocephalus). I].

Investigated the morphogenesis of the nasal structures of the chondrocranium and determatocranium in 15 embryos and foetuses of the sperm whale (Physeter macrocephalus). In the very early stages of the morphogenesis, the nasal capsule of Physeter shows a conspicuous similarity with that of all other odontocetes. In the following stages there are some important differences. Most peculiar is the occurrence of the cartilaginous tectum nasi with the cupulae nasi anteriores, elements which are reduced in all other odontocetes. This cartilaginous complex as a slender band projects obliquely forward from the upper edge of the anterior septal margin. It is free, i.e. not accompanied by membraneous bones. The complex represents the most important factor in the morphogenesis and growth of the characteristic big forehead in Physeter, which contains the spermaceti organ unique within the odontocetes. Other important differences concern the changes in the orientation of the nasal passages and the adjacent skeletal structures. Nevertheless, these differences have to be taken as specializations related to the development of the far-advanced spermaceti organ. As a whole, the embryonic nasal structures in Physeter belong to the same general type of nasal capsule which is common to all odontocetes. The results presented here suggest a close phylogenetic relationship between Physeter and the other Odontoceti.

Animals↗
PubMed1986

A kinetic description of ligand binding to sperm whale myoglobin.

Nanosecond recombination time courses were measured by photolyzing O2, NO, CO, methyl, ethyl, n-propyl, n-butyl, and tert-butyl isocyanide complexes of sperm whale myoglobin with a 30-ns laser pulse at pH 7, 20 degrees C. Absorbance was measured both during and after the excitation pulse and as a function of laser light intensity. The results were analyzed quantitatively in terms of a three-step reaction scheme, MbX in equilibrium B in equilibrium C in equilibrium Mb + X, where Mb is myoglobin, B represents a geminate state in which the ligand is present in the distal pocket but not covalently bound to the iron atom, and C, a state in which the ligand is still embedded in the protein but further away from the heme group. The fitted rate parameters were required to be consistent with the observed overall quantum yield, Q, which had been measured independently using much longer (approximately 0.5 ms) xenon flash pulses. Three major conclusions were derived from these analyses. First, the overall quantum yield of the ligand complex is determined primarily by the competition between the rate of iron-ligand bond formation from the initial photoproduct, kB----MbX, and the rate of migration away from state B, kB----C. For example, kB----C approximately equal to 30-100 microseconds-1 for all three gaseous ligands, whereas both Q and kB----MbX vary over 3 orders of magnitude (i.e. NO, Q = 0.001, kB----MbX approximately equal to 16,000 microseconds-1; O2, Q = 0.1, kB----MbX approximately equal to 500 microseconds-1; CO, Q = 1.0, kB----MbX approximately equal to 2 microseconds-1). Second, for NO, O2, and the isonitriles, the rate-limiting step in the overall association reaction starting from ligand in solution is the formation of state B. The rate constant for this process varies from 2 X 10(7) M-1 s-1 for the gaseous ligands to 0.02-1.4 X 10(5) M-1 s-1 for the isonitriles. In contrast, the B to MbX transition is limiting for CO binding. Third, for all the ligands except CO, the overall rate of dissociation is limited significantly both by the rate of thermal bond disruption, kMbX----B, and the competition between geminate recombination and migration away from the distal pocket (i.e. kB----C/(kB----MbX + kB----C]. In the case of CO, the rate of bond disruption is equal to the observed dissociation rate constant.

Animals↗
PubMed1987

Functional effects of heme orientational disorder in sperm whale myoglobin.

The optical absorption and ligand binding properties of newly reconstituted sperm whale myoglobin were examined systematically at pH 8, 20 degrees C. The conventional absorbance and magnetic circular dichroism spectra of freshly reconstituted samples were identical to those of the native protein. In contrast, reconstituted azide or CO myoglobin initially exhibited less circular dichroism in the Soret wavelength region than native myoglobin. These data support the theory proposed by La Mar and co-workers (La Mar, G. N., Davis, N. L., Parish, D. W., and Smith, R. M. (1983) J. Mol. Biol. 168, 887-896) that protoheme inserts into apomyoglobin in two distinct orientations. The equilibrium and kinetic parameters for O2 and CO binding to newly reconstituted myoglobin were observed to be identical to those of the native protein. Thus, the orientation of the heme group has no effect on the physiological properties of myoglobin. This result is in disagreement with the preliminary report of Livingston et al. (Livingston, D. J., Davis, N. L., La Mar, G. N., and Brown, W. D. (1984) J. Am. Chem. Soc. 106, 3025-3026) which suggested that the abnormal heme conformation exhibited a 10-fold greater affinity and association rate constant for O2 binding. Significant kinetic heterogeneity was observed only for long-chain isonitrile binding to newly reconstituted myoglobin, and even in these cases, the rate constants for the abnormal and normal heme conformations differed by less than a factor of 4.

Animals↗
PubMed1985

[Additional skeletal elements in the nasal skull structure of Phocoena phocoena and the development of the nasal region in toothed whales].

Small nasal ossicles, occasionally occurring on the caudal border of the premaxillary bones in Phocoena and some other toothed whales (Odontoceti) up to now, were considered the remnants of maxilloturbinalia. The latter, however, originate from the cartilaginous lateral wall of the embryonal nasal capsule, whereas the ossicles mentioned are remnants of the nasal floor cartilages. These additional nasal structures are homologous with the lamina transversalis anterior, and also contain the material of the cartilago paraseptalis. In comparison with the quadrupedal terrestrial mammals, the skull of odontocetes shows some important differences in development. In the nasal region, the nasal tract is shifted backward from the top of the snout to the vertex of the head, while the bony rostrum projects far forward. These changes can already be observed during the early morphogenesis of skull. We have examined embryos of Phocoena, Lagenorhynchus, and Monodon, 16 different developmental stages altogether, representing the most complete material ever examined for this purpose. There is a marked developmental trend from a complicated nasal capsule, consisting of many isolated cartilages, to a simple reduced structure, being composed of some fused cartilages only. Whereas Monodon, Lagenorhynchus, and Globicephala still possess some of the original ancestral features, common to all mammals, Phocoena in this respect is the most advanced odontocete which has been investigated so far. In Phocoena, the tectum nasi and the lateral wall of the nasal capsule are widely reconstructed in embryonal life, turned upright and displaced caudally; thus it lies immediately in front of neurocranium. The floor of the original nasal capsule persists in 2 elements only, the lamina transversalis anterior and the paraseptal cartilage, both largely fusing with each other and losing their connection with the lateral nasal wall. During early morphogenesis they move to the top of the head, expanding along the upper border of the nasal septum. Together with the rostral part of the nasal septum, they join in the prolongation of the dolphin head and hold the space for the exoskeletal dermal bones which develop later. There is a direct connection between the lamina transversalis anterior and the premaxillary bone, as well as between the cartilago paraseptalis and the vomer. These topographical relationships persist until the adult stage of odontocetes.

Animals↗
PubMed1985

Electrostatic interactions in sperm whale myoglobin. Site specificity, roles in structural elements, and external electrostatic potential distributions.

The electrostatic free energy contribution to the stability of sperm whale ferrimyoglobin was evaluated according to the static accessibility modified Tanford-Kirkwood model. The electrostatic free energy contribution of each distinct structural element was divided into one term arising from interactions between it and other elements (interelemental) and another from interactions within the particular element itself (intraelemental). At pH 7 the majority of the terms were found to be stabilizing. The interelemental terms are the dominant ones for most structural elements. The small interelemental terms of the C and D helices are compensated by large intraelemental interactions which stabilize these short helices. Perturbations in pH can be accommodated by the structural elements through a redistribution of stabilizing and destabilizing interactions. The electrostatic potentials calculated at the surface of the protein indicate that the internal compensation of local potentials achieved during folding results in a generally neutral protein-solvent interface save for two distinct areas of nonzero potential. The accessibility of each charged atom to solvent was analyzed in terms of the surface area lost to charged, polar and nonpolar atoms separately. The net solvent accessibility lost parallels closely that lost to nonpolar atoms alone, indicating a specific role for nonpolar atoms in defining dielectric shielding of charged atoms, aside from their participation in the well-known hydrophobic interactions.

Amino Acids↗
PubMed1978

Antigen dose and strain variation as factors in the genetic control of the immune response to sperm whale myoglobin.

The primary and secondary immune response to the antigen sperm whale myoglobin was investigated in DBA/2, 129 and B10.BR mice over a dose range of immunization from 10 to 2000 microgram. Using an antigen excess technique, the quantity of antibody produced after secondary immunization followed a sigmoidal dose-response curve and the maximal plateau level was found to be different for each strain of mice. Furthermore, the genetic control of the immune response was investigated in twelve different inbred strains of mice following secondary immunization with 500 microgram of myoglobin. A continuous distribution for the mean antibody responses was obtained for the twelve different strains of mice. High responsiveness was associated with H-2 haplotypes d, f and k located on chromosome 17, the non-agouti gene 'a' located on chromosome 2 and the chinchilla gene 'c(ch)' located on chromosome 7. It is concluded that either a large number of IR-genes to myoglobin are present in many loci located on different chromosomes or the antibody differences could be explained by a cross-tolerance mechanism requiring no IR-genes at all.

Animals↗
PubMed1984

[Luteinizing hormone of the sperm whale. Isolation, separation into subunits and study of the amino acid sequence of the alpha-subunit].

The luteinizing hormone isolated from sperm-whale pituitary was separated into two subunits, alpha- and beta-, by ion-exchange chromatography on sulfoethyl-Sephadex. The hormone subunits were reconstituted, carboxymethylated and cleaved by BrCN and proteolytic enzymes. In order to block tryptic hydrolysis at lysine residues the alpha-subunit was subjected to maleylation. Large-sized fragments of BrCN were cleaved by chymotrypsin and trypsin, while large-sized fragments of trypsin were split by chymotrypsin. The resulting peptides were separated by gel filtration on Sephadex, ion-exchange chromatography on Aminex A-5 and thin-layer partition chromatography on cellulose. The amino acid sequence of the peptides was determined by the Edman method, using identification of the N-terminal amino acids in a reaction with dansyl chloride or dimethylaminoazobenzene-4-isothiocyanate. It was shown that the alpha-subunit of the luteinizing hormone is a peptide chain consisting of 96 amino acid residues with covalently linked carbon chains at asparagine residues at positions 56 and 82. The N-terminal amino acid of the alpha-subunit is phenylalanine, the C-terminal amino acid is serine. The alpha-subunit is heterogeneous at the N-end, i. e. beside phenylalanine it contains threonine and trace amounts of proline, aspartate, glutamate and glycine.

Amino Acid Sequence↗
PubMedDate not supplied

Electrical whaling--a review.

Theoretically, for anatomical reasons, the use of electric current should be an efficient killing method on whales, and a number of experiments with electric harpoons have therefore been previously carried out. Even though killing time was reduced in relation to the use of the detonating grenade harpoon, results were inconsistent, mainly because of technical problems. The method therefore seems to be too uncertain to be used as an alternative to present catching methods.

Animals↗