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PubMed1995

Survival of parvalbumin-immunoreactive neurons in the gerbil hippocampus following transient forebrain ischemia does not depend on HSP-70 protein induction.

HSP-70 was induced in the gerbil following 20 min of forebrain ischemia. The induction, as revealed with immunohistochemistry, is stronger and longer-lasting in CA3 and dentate gyrus than in CA1. Most neurons in this region, except GABAergic interneurons containing the calcium-binding protein parvalbumin, eventually cease to live as a result of delayed cell death. Double-labeling of inducible HSP-70 and parvalbumin has shown that no co-localization occurs in the hippocampus and neocortex of the gerbil in this model of transient forebrain ischemia. These results show that different thresholds of sensitivity and vulnerability exist for different subpopulations of neurons in the ischemic hippocampus, and suggest that HSP-70 protein induction is probably not essential for the survival of particular neuronal subpopulations subjected to transient ischemia.

Animals↗
PubMed1996

Parvalbumin-like immunoreactivity of layer V pyramidal cells in the motor and somatosensory cortex of adult primates.

Most previous immunocytochemical studies have indicated that the calcium-binding protein parvalbumin is present only in non-pyramidal neurons of the adult cerebral cortex. Using nickel and cobalt to enhance the diaminobenzidine reaction product, we observed large layer V pyramidal cells with parvalbumin-like immunoreactivity in the primary motor cortex (area 4) and somatosensory cortex of adult macaque monkeys and galagos, including giant Betz cells in area 4.

Animals↗
PubMed1985

Crystal structure study of Opsanus tau parvalbumin by multiwavelength anomalous diffraction.

The crystal structure of a small calcium-binding protein, the parvalbumin IIIf from Opsanus tau in which Tb was substituted for Ca, has been analysed by multiwavelength anomalous diffraction. Data at a resolution of 2.3 A were collected at three wavelengths near the L3 absorption edge of Tb (1.645-1.650 A), using the synchrotron radiation emitted by a storage ring and a multiwire proportional counter. The phases of the reflections were determined from this single derivative, without native data. Prior to any refinement, the resulting electron density map shows a good agreement with the model of the homologous carp parvalbumin in regions of identical amino-acid sequence.

Animals↗
PubMed1992

Evidence that deprotonation of serine-55 is responsible for the pH-dependence of the parvalbumin Eu3+ 7F0-->5D0 spectrum.

The Eu(III)7F0-->5D0 excitation spectra of the parvalbumins are highly pH-dependent. Below pH 6.0, they exhibit a sharp, partially resolved doublet centered near 5,795 A. However, as the pH is raised, the spectrum becomes increasingly dominated by a much broader signal near 5,784 A. This behavior has been traced to the Eu(III) ion bound at the CD site, but the identity of the moiety undergoing deprotonation remains uncertain. Site-specific mutagenesis studies on the parvalbumin-like protein known as oncomodulin now suggest that the species in question is a liganding serine hydroxyl group. Specifically, replacement of serine-55 by aspartate (the residue present at the corresponding position in the EF site) affords a protein that retains two functional lanthanide binding sites, but fails to undergo the pH-dependent spectral alteration. By contrast, replacement of aspartate-59 by glycine (the corresponding EF site residue) fails to abolish the pH-dependent behavior.

Animals↗
PubMed1988

Crystal structure determination and refinement of pike 4.10 parvalbumin (minor component from Esox lucius).

The crystal and molecular structure of the minor component of pike parvalbumins has been determined at 1.93 A resolution by molecular replacement (1 A = 0.1 nm). The crystals are orthorhombic, space group P2(1)2(1)2 with a = 59.62 A, b = 59.83 A and c = 26.35 A. A location of the secondary cation binding site is proposed for this parvalbumin of the beta phylogenetic series.

Amino Acid Sequence↗
PubMed1988

Interaction of parvalbumin of pike II with calcium and terbium ions.

Fluorimetric titrations of parvalbumin II (pI 4.2) of pike (Pike II) with Ca2+ and Tb3+ show the CD and EF binding sites to be non-equivalent. The intrinsic binding constants of the strong and the weak sites obtained for Ca2+ are: KsCa = 1.6.10(8) M-1; KwCa = 6.6.10(5) M-1. Differences of the order of 100% were encountered between the Tb3+ binding constants obtained with four different versions of titration. Their average values are: KsTb = 1.9.10(11) M-1; KwTb = 1.0.10(7) M-1. The distances of the strong and the weak sites from the singular Tyr-48, rs = 9.5 A and r2 = 11.5 A, were derived from Förster-type energy transfer and proved compatible with the X-ray structure of parvalbumin III (pI 4.2) of carp (CarpIII). From the distances, it is suggested that CD is the strong and EF the weak metal-binding site of PikeII. Tb3+ was shown by CD spectroscopy to have the same structural effect on PikeII as Ca2+. Removal of the metal ions from PikeII results in a decrease of helix content as monitored by CD spectroscopy. This decrease is larger than that in CarpIII. A concomitant decrease of the fluorescence quantum yield at nearly constant decay time is indicative of mainly static quenching, probably by the non-coordinating carboxylate groups. The maximum helix content is almost completely reestablished upon binding of the first metal ion. However, small changes of the energy transfer in PikeII with one terbium ion bound to the strong site indicate fine structural rearrangements of the strong binding site when Ca2+ is bound to the weak one.

Animals↗
PubMed1990

Europium(III) ion luminescence as a structural probe of parvalbumin isotypes.

The 7F0----5D0 transition of Eu3+ is used to investigate the metal ion binding sites of five parvalbumin isotypes. Comparisons are based on the resolution of the Eu3+ excitation spectrum with a computer program using the Marquardt nonlinear regression algorithm. The Lorentzian-Gaussian product function provides the most effective approximation to the shape of the peaks, the positions of which were found to be related to differences in the amino acid residues at the binding sites. Below pH 6, spectra consist of two peaks near 579 nm, but as the pH is raised, the two peaks gradually diminish and two new, much broader peaks appear at 577 and 578 nm. The lower wavelength peak, at low pH, and the peak at 577 nm, at high pH, are assigned to the CD site. The two sites have nearly equal affinities for Eu3+ except in the northern pike III (pI 5.0) isotype. The excitation spectra are compared to that of the carp III (pI = 4.25) parvalbumin for which the complete crystal structure is available. This structure forms the basis for the molecular modeling studies of the altered binding sites. Preliminary results are presented regarding differences in solvent exposure of the CD and EF sites based on collision-induced energy transfer to [Co(NH3)6]3+.

Algorithms↗
PubMed1991

Noncovalent complex between domain AB and domains CD*EF of parvalbumin.

The interaction between domain AB and domains CD*EF of pike parvalbumin III has been studied by intrinsic fluorescence spectroscopy. In the presence of Ca2+ ions, parvalbumin fragment 38-108 containing two calcium binding sites interacts with the short peptide 1-37 with association constant 10(5.3 +/- 0.5) M-1. Removal of Ca2+ ions results in the disappearance of the interaction. The affinity of the complex of the two fragments for calcium is 50-times higher than the affinity of the isolated fragment 38-108, but slightly lower than that of the intact protein.

Binding Sites↗
PubMed1996

Human recombinant alpha-parvalbumin and nine mutants with individually inactivated calcium- and magnesium-binding sites: biochemical and immunological properties.

Human recombinant alpha-parvalbumin (PVwt) and nine mutant proteins, containing inactivating substitutions at positions essential for Ca2+ binding in the CD Ca(2+)-binding site (PVE62V, PVD51A, PVD51A,62V), the EF site (PVE101V, PVD90A, PVD90A,E101V) or in both (PVE62V,E101V, PVD51A,D90A, PVD51A,E62V,D90A,E101V), were expressed and purified. Flow dialysis revealed that PVwt binds 2 Ca2+ with equal K'Ca, of 2.3 x 10(7) M-1 and that Mg2+ competes with a K'Mg.compet. of 4.9 x 10(3) M-1. The three mutants with an inactivated CD site bind 1 Ca2+ with K'Ca, of 2.0 to 2.3 x 10(7) M-1 and K'Mg.compet. of 3.4 to 4.6 x 10(3) M-1, i.e. very similar to those of PVwt. The mutants with an inactivated EF site bind 1 Ca2+ with K'Ca values of 7.9 x 10(6), 4.5 x 10(6) and 3.6 x 10(6) M-1 for PVD91A, PVE102V and PVE101V,D91A, respectively. The K'Mg.compet values of these mutants are about 4-times lower than in PVwt. The three mutants with both sites inactivated bind neither Ca2+ nor Mg2+. After excitation at 259 nm, human PV, which contains neither Tyr nor Trp, shows maximal fluorescence emission at 283 nm. Binding of either Ca2+ or Mg2+ to PVwt or to mutants with an inactivated EF site lead to a 1.8-fold decrease in fluorescence intensity, whereas the mutants with an inactivated CD show only a very slight decrease upon binding of Ca2+ or Mg2+. Specific antibodies against human alpha-parvalbumin were raised in rabbits. Their reactivity was tested against the mutant proteins, and their potential value for location and functional studies was investigated.

Animals↗
PubMed1990

The amino acid sequence of avian thymic hormone, a parvalbumin.

The complete amino acid sequence of 'avian thymic hormone' (ATH), a protein from thymus tissue that appears to promote immune maturation in chicken bone marrow cells in culture, is presented. The sequence was obtained from sequences of ATH peptides isolated by HPLC after tryptic, chymotryptic, peptic or S aureus V8 protease digestions. The protein is a parvalbumin consisting of 108 residues with a blocked amino terminus, a single cysteine, tyrosine, proline and arginine and no histidine, methionine or tryptophan. This is the first amino acid sequence of a parvalbumin which is not derived from muscle tissue.

Amino Acid Sequence↗
PubMed1985

Fluorescence quenching of the buried tryptophan residue of cod parvalbumin.

Cod parvalbumin (isotype III) is a single tryptophan-containing protein. The fluorescence characteristics of this tryptophan residue (lambda em approximately 315 nm) suggest that it is buried from solvent and that it is located in an apolar core of the protein. Solute quenching studies of the tryptophan fluorescence of parvalbumin reveal dynamic quenching rate constants, kq, of 1.1 X 10(8) and 2.3 X 10(9) M-1 s-1 (at 25 degrees C) with acrylamide and oxygen, respectively, as quenchers. From temperature dependence studies, activation energies of 6.5 +/- 1.5 and 6.0 +/- 0.5 kcal/mol are found for acrylamide and oxygen quenching. The kq for acrylamide quenching is found to be relatively unchanged (+/- 10%) by an 8-fold increase in the bulk viscosity (glycerol/water mixture). These temperature and viscosity studies argue that the acrylamide quenching process involves a dynamic penetration of the quencher, facilitated by fluctuations in the protein's structure.

Acrylamide↗
PubMed1987

Stopped-flow kinetic studies of Ca(II) and Mg(II) dissociation in cod parvalbumin and bovine alpha-lactalbumin.

The dissociation kinetics of complexes of bovine alpha-lactalbumin and cod parvalbumin with Ca(II) and Mg(II) ions induced by mixing of a Ca(II)- or MG(II)-loaded protein with a chelator of divalent cations (EDTA or EGTA) have been studied by means of the stopped-flow method with intrinsic protein fluorescence registration. Within the temperature interval from 10 to approx. 37 degrees C kinetic curves for Ca(II) removal from alpha-lactalbumin are monoexponential with a rate constant ranging from 0.006 to 1 s. Taking into account the rather low rate of fluorescence changes, one can assume that the limiting stage in this case is the dissociation of the single bound Ca(II) ion from the protein and not a conformational transition which occurs after Ca(II) dissociation. At temperatures above 37 degrees C the kinetic curves require at least two exponential terms for a satisfactory fit. The second exponential seems to be due to denaturation of the apo form of alpha-lactalbumin which takes place at these temperatures. The values of the dissociation rate constants for Mg(II) bound to alpha-lactalbumin practically coincide with those for Ca(II). Within the temperature interval 10-30 degrees C the kinetic curves for Ca(II) and Mg(II) removal from parvalbumin are best fitted by a sum of two exponential terms identified as arising from the dissociation of cations from the two binding sites.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Parvalbumin and vitamin D-dependent calcium-binding protein (Mr 28,000): comparison of their localization in the cerebellum of normal and rachitic rats.

Two neuronal and Ca2+-binding proteins, parvalbumin and a vitamin-D-dependent calcium-binding protein (CaBP; Mr = 28,000) were localized immunohistochemically in the rat cerebellum, which is the brain region containing the highest concentration of them both. Parvalbumin was present in Purkinje, basket and stellate cells of the molecular layer, whereas CaBP was only present in Purkinje cells. The concentrations of both proteins, measured immunohistochemically and biochemically, were unaffected by the vitamin D status of the rats.

Animals↗
PubMed1989

GABAergic hippocampal neurons resistant to ischemia-induced neuronal death contain the Ca2(+)-binding protein parvalbumin.

Bilateral transient occlusion of carotid arteries in gerbils for 7 min results in delayed neuronal cell death in hippocampal field CA1. Local gamma-aminobutyric acid (GABA)ergic neurons survive the ischemic insult. Here we show that interneurons in gerbil hippocampus are parvalbumin-immunoreactive, that they contain the GABA-synthetizing enzyme glutamic acid decarboxylase (GAD), and that they are resistant to the effects of ischemia, being present up to 28 days after the insult. It might be concluded that the presence of the Ca2+-binding protein parvalbumin protects the GABAergic neurons from the deleterious consequences of ischemia-induced excitotoxin-mediated Ca2+-influx.

Animals↗
PubMed1990

Parvalbumin immunoreactivity in the central auditory system of the gerbil: a developmental study.

Changes in parvalbumin-like immunoreactivity were studied during ontogenetic development of the central auditory system of the Mongolian gerbil (Meriones unguiculatus). The nucleus of the trapezoid body contained cells that could be stained on the day of birth while in the superior olivary complex, prominent staining of cell somata was only found at P15 (postnatal day 15). Neurons located in the ventral nucleus, in the dorsal nucleus of the lateral lemniscus and in the inferior colliculus developed parvalbumin immunoreactivity mostly between P11-P15 (ventral nucleus), P15-P19 (dorsal nucleus) and P15-P19 (inferior colliculus), respectively. The accumulation of PV correlates reasonably well with the functional maturation of the neurons in these areas.

Animals↗
PubMed1991

The immunocytochemical distribution of calbindin-D28k and parvalbumin in identified neurons of the pulvinar-lateralis posterior complex of the cat.

The calbindin-D28k and parvalbumin immunoreactivities of the neurons of the pulvinar-lateral posterior complex (Pul-LP) were studied in the cat. The neurons of the Pul-LP projecting to the cerebral cortex were identified by a retrogradely transported tracer injected in the suprasylvian gyrus. Two populations of cells were found, a calbindin-D28k-immunoreactive, large-diameter population and a parvalbumin-immunoreactive, small-diameter group. The two kinds of cells are closely intermingled. The former includes the neurons retrogradely marked, and therefore projecting to the suprasylvian gyrus. The latter includes neurons which were not retrogradely marked, and therefore presumably intrinsic elements.

Animals↗
PubMed1995

Parvalbumin-positive small myelinated fiber bundles in anterior marginal areas in the human cervical cord.

During pathological examinations of amyotrophic lateral sclerosis (ALS) patients, we noticed that bundles of dense small myelinated fibers were relatively well preserved in the anterior marginal areas of the cervical cords in a few ALS patients with diffuse myelin pallor. Moreover, these fibers were strongly immunostained by anti-parvalbumin antiserum. These parvalbumin-positive fiber bundles were also seen in other ALS and non-ALS patients, and they were continuously traced up to the spinothalamic tract areas of the medulla oblongata. Therefore, it is suggested that these fiber bundles belong mainly to the ventral spinothalamic tract. We considered that these fiber bundles became conspicuous in shape since other areas in the anterolateral funiculus showed myelin pallor in such ALS patients.

Adult↗
PubMed1990

Soluble calcium-binding proteins: parvalbumins and calmodulin from eel skeletal muscle.

1. Eel skeletal muscle contains three parvalbumin isoforms. The overall parvalbumin concentration in the muscle is 0.5 mmol kg-1 wet weight. 2. Calmodulin (0.1 mumol kg-1 wet weight) was purified by extraction with ethylenediamine tetraacetate-containing buffer, fractionation with trichloroacetic acid and separation by ion exchange chromatography on DEAE-cellulose and by molecular sieving on Ultrogel AcA 54. 3. Troponin-C-free calmodulin was obtained by fast protein liquid chromatography on a Mono Q column.

Anguilla↗