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1.
Saccharomyces cerevisiae and mammals concerning the mechanisms of the translocation step and discuss the roles of the proteins implicated in this
process.
Received: 5 June 1996/Revised: 20 September 1996 相似文献
2.
A Novel Family of Ubiquitous Heavy Metal Ion Transport Proteins 总被引:33,自引:0,他引:33
We describe a novel diverse family of metal ion transporter (CDF) proteins (the cation diffusion facilitator (CDF) family)
with members occurring in both prokaryotes and eukaryotes. Thirteen sequenced protein members of the CDF family have been
identified, several of which have been shown to transport cobalt, cadmium and/or zinc. All members of the CDF family possess
six putative transmembrane spanners with strongest conservation in the four N-terminal spanners, and on the basis of the analyses,
we present a unified structural model. Members of the family are shown to exhibit an unusual degree of size variation, sequence
divergence, and differences in cell localization and polarity. The phylogenetic tree for the CDF family reveals that prokaryotic
and eukaryotic proteins cluster separately. It allows functional predictions for some uncharacterized members of this family.
A signature sequence specific for the CDF family is derived.
Received: 15 July 1996/Revised: 21 October 1996 相似文献
3.
Interspersed repeats that emerged at different evolutionary times are informative in mammalian phylogeny. Here we show that
the ancient short interspersed elements (SINEs) ARE1 and ARE2 are abundantly present in the genomes of artiodactyls and cetaceans
but not in other mammalian genomes. This supports the classification of the cetaceans with the artiodactyls by a shared character
that is unlikely to be the result of convergence.
Received: 16 October 1996 / Accepted: 13 December 1996 相似文献
4.
The ubiquitous major intrinsic protein (MIP) family includes several transmembrane channel proteins known to exhibit specificity
for water and/or neutral solutes. We have identified 84 fully or partially sequenced members of this family, have multiply
aligned over 50 representative, divergent, fully sequenced members, have used the resultant multiple alignment to derive current
MIP family-specific signature sequences, and have constructed a phylogenetic tree. The tree reveals novel features relevant
to the evolutionary history of this protein family. These features plus an evaluation of functional studies lead to the postulates:
(i) that all current MIP family proteins derived from two divergent bacterial paralogues, one a glycerol facilitator, the
other an aquaporin, and (ii) that most or all current members of the family have retained these or closely related physiological
functions.
Received: 19 April 1996/Revised: 3 June 1996 相似文献
5.
J. Robert Macey Allan Larson Natalia B. Ananjeva Theodore J. Papenfuss 《Journal of molecular evolution》1997,44(6):660-674
A phylogenetic tree for major lineages of iguanian lizards is estimated from 1,488 aligned base positions (858 informative)
of newly reported mitochondrial DNA sequences representing coding regions for eight tRNAs, ND2, and portions of ND1 and COI.
Two well-supported groups are defined, the Acrodonta and the Iguanidae (sensu lato). This phylogenetic hypothesis is used
to investigate evolutionary shifts in mitochondrial gene order, origin for light-strand replication, and secondary structure
of tRNACys. These three characters shift together on the branch leading to acrodont lizards. Plate tectonics and the fossil record indicate
that these characters changed in the Jurassic. We propose that changes to the secondary structure of tRNACys may destroy function of the origin for light-strand replication which, in turn, may facilitate shifts in gene order.
Received: 28 May 1996 / Accepted: 27 December 1996 相似文献
6.
We have isolated a 29,000-Da carbonic anhydrase (CA) protein from the zebrafish, Danio rerio, sequenced two peptide fragments, and tentatively identified it as a high-activity CA by inhibition kinetics. We have also
characterized a 1,537-bp message whose deduced sequence of 260 amino acids matches that of the isolated protein. This CA is
clearly an α-CA based on the similarity of its sequence to that of other members of the α-CA gene family. A phylogenetic analysis
suggested CAH-Z diverged after the branching of the CA-V and CA-VII genes and prior to the duplications that generated the
CA-I, CA-II, and CA-III genes of amniotes. This marks the first characterization of the mRNA and its protein product from
the CA gene of a teleost.
Received: 31 March 1996 / Accepted: 8 September 1996 相似文献
7.
Phosphonic acids are the only phosphorus-containing organic compounds detected in the Murchison meteorite. We earlier described
the synthesis of methyl-, hydroxymethyl-, and 1-hydroxyethyl phosphonic acids using sodium phosphite as a source of phosphite
radicals. We now show that ultraviolet irradiation of dilute aqueous solutions of acetylene in the presence of sodium phosphite
leads to the synthesis of vinyl phosphonic acid. At neutral to basic pH, vinyl phosphonic acid reacts under photochemical
conditions to produce phosphonoacetaldehyde and 2-hydroxyethyl phosphonic acid as the major products, as well as smaller yields
of 1-hydroxyethyl phosphonic acid, phosphonoacetic acid, and ethyl phosphonic acid. Of these products, phosphonoacetaldehyde
is particularly interesting as a potential precursor of prebiotic carbohydrate derivatives.
Received: 22 July 1996 / Accepted: 13 September 1996 相似文献
8.
Of Worms and Men: An Evolutionary Perspective on the Fibroblast Growth Factor (FGF) and FGF Receptor Families 总被引:6,自引:0,他引:6
François Coulier Pierre Pontarotti Régine Roubin Helge Hartung Mitchell Goldfarb Daniel Birnbaum 《Journal of molecular evolution》1997,44(1):43-56
FGFs (fibroblast growth factors) play major roles in a number of developmental processes. Recent studies of several human
disorders, and concurrent analysis of gene knock-out and properties of the corresponding recombinant proteins have shown that
FGFs and their receptors are prominently involved in the development of the skeletal system in mammals. We have compared the
sequences of the nine known mammalian FGFs, FGFs from other vertebrates, and three additional sequences that we extracted
from existing databases: two human FGF sequences that we tentatively designated FGF10 and FGF11, and an FGF sequence from
C?norhabditis elegans. Similarly, we have compared the sequences of the four FGF receptor paralogs found in chordates with four non-chordate FGF
receptors, including one recently identified in C. elegans. The comparison of FGF and FGF receptor sequences in vertebrates and nonvertebrates shows that the FGF and FGF receptor families
have evolved through phases of gene duplications, one of which may have coincided with the emergence of vertebrates, in relation
with their new system of body scaffold.
Received: 6 April 1996 / Accepted: 5 July 1996 相似文献
9.
Takehiro Kusakabe Isato Araki Noriyuki Satoh William R. Jeffery 《Journal of molecular evolution》1997,44(3):289-298
The origin and evolutionary relationship of actin isoforms was investigated in chordates by isolating and characterizing
two new ascidian cytoplasmic and muscle actin genes. The exon–intron organization and sequences of these genes were compared
with those of other invertebrate and vertebrate actin genes. The gene HrCA1 encodes a cytoplasmic (nonmuscle)-type actin, whereas the MocuMA2 gene encodes an adult muscle-type actin. Our analysis of these genes showed that intron positions are conserved among the
deuterostome actin genes. This suggests that actin gene families evolved from a single actin gene in the ancestral deuterostome.
Sequence comparisons and molecular phylogenetic analyses also suggested a close relationship between the ascidian and vertebrate
actin isoforms. It was also found that there are two distinct lineages of muscle actin isoforms in ascidians: the larval muscle
and adult body-wall isoforms. The four muscle isoforms in vertebrates show a closer relationship to each other than to the
ascidian muscle isoforms. Similarly, the two cytoplasmic isoforms in vertebrates show a closer relationship to each other
than to the ascidian and echinoderm cytoplasmic isoforms. In contrast, the two types of ascidian muscle actin diverge from
each other. The close relationship between the ascidian larval muscle actin and the vertebrate muscle isoforms was supported
by both neighbor-joining and maximum parsimony analyses. These results suggest that the chordate ancestor had at least two
muscle actin isoforms and that the vertebrate actin isoforms evolved after the separation of the vertebrates and urochordates.
Received: 20 June 1996 / Accepted: 16 October 1996 相似文献
10.
Unilamellar liposomes with native phospholipid fatty acid composition were prepared from rat liver mitochondrial inner membrane
phospholipids by extrusion in medium containing 50 mm potassium. They were diluted into low potassium medium to establish a transmembrane potassium gradient. A known membrane
potential was imposed by addition of valinomycin, and proton flux into liposomes was measured. Valinomycin in the range 10
pm–1nm was sufficient to fully establish membrane potential. Valinomycin concentrations above 3 nm catalyzed additional proton flux and were avoided. At 300 pm valinomycin, proton flux depended nonlinearly on membrane potential. At 160 mV membrane potential the flux was 30 nmol H+/min/mg phospholipid—approximately 5% of the proton leak flux under comparable conditions in isolated mitochondria, indicating
that leak pathways through bulk phospholipid bilayer account for only a small proportion of total mitochondrial proton leak.
Received: 5 August 1996/Revised: 1 October 1996 相似文献
11.
Previous reports have demonstrated that large cationic polypeptides (of molecular mass 5,000 daltons or greater) cause an
increase in the apical membrane conductance of the rabbit urinary bladder epithelium. This report investigates the effects
of the small cationic molecule polymyxin B (PX: a 1,400 dalton antibiotic) on the permeability of the rabbit urinary bladder.
The addition of micromolar concentrations of polymyxin B to the luminal solution of the rabbit urinary bladder resulted in
an increase in the transepithelial conductance of the bladder. The magnitude of the increase in the conductance was dependent
upon the concentration of PX, and the polarity and magnitude of the apical membrane potential. As the apical membrane potential
was made more cell interior negative, the larger was the increase in the membrane conductance. This voltage-dependent increase
in conductance was an exponential function of the applied voltage, with a negligible increase in conductance occurring when
the membrane potential was cell interior positive. Upon changing the membrane voltage from cell interior positive to negative,
there was a delay before there was a measurable change in the membrane conductance. The longer the apical membrane was exposed
to PX, the more poorly reversible was its effect on the transepithelial conductance, suggesting a toxic effect of PX on this
epithelium.
Received: 9 May 1996/Revised: 17 July 1996 相似文献
12.
In this study, electrorotation spectra of individual cells (that is, frequency dependence of cell rotation speed) have been
proved to yield information not only about the passive electric properties of cell constituents, but also about the presence
of mobile charges within the plasma membrane being part of ion carrier transport systems. Experiments on human erythrocytes
pretreated with the lipophilic anion dipicrylamine (DPA) gave convincing evidence that these artificial mobile charges adsorbed
to the plasma membrane contributed significantly to the rotational spectrum at relatively low conductivity of the external
medium (2–5 mS m−1). Theoretical integration of the mobile charge concept into the single-shell model (viewing the cell as a homogenous sphere
surrounded by a membrane) led to a set of equations which predicted electrorotational behavior of DPA-treated cells in dependence
on medium conductivity. The quantitative data on the partition and the transmembrane translocation rate of the DPA anion extracted
from the experimental rotational spectra agreed well with the corresponding literature values.
Received: 14 February 1996/Revised: 29 May 1996 相似文献
13.
Radu Popa 《Journal of molecular evolution》1997,44(2):121-127
A sequential model is proposed regarding the origin of biological chirality. Three major stages are presumed: a symmetry
breaking (prebiotic chiral disruption in enantiomeric mixtures of monomers), a chiral amplification (prebiotic increase of
the chiral character of the monomers affected first by the symmetry breaking), and a chiral expansion (proto biological increase
of the chiral character and spread of the chirality to molecules which were less affected by prebiotic chiralizations). As
a symmetry-breaking mechanism, the model proposed by Deutsch (1991) is used, which involves a dissymmetric exposure of amino
acids (AA) to ultraviolet circularly polarized light (UV-CPL) on evaporative seashores. It is presumed that the chiral amplification,
up to a protobiologic significance, was influenced by a periodic overlapping of two abiotic events, a synchronization between
tidal-based hydrous–anhydrous cycles, and littoral asymmetric photolysis cycles. This long-term astronomic asymmetry acted
around 3.8–4.2 billion years ago and was unique to the Earth in our solar system. It is also presumed that the abiotic symmetry
breaking is heterogenous, that only a few l-AAs were used in the beginning, and that the chirality expanded later to all 20 AAs based on a coevolutionary strategy of
the genetic code and on a physiological relationship between AAs. In this scenario the d-chirality of pentoses in polynucleotides was attributed to both d-pentose/l-AA relationships and to a structural evolution.
Received: 10 May 1996 / Accepted: 13 August 1996 相似文献
14.
Phylogenetic Reconstruction Using an Unsupervised Growing Neural Network That Adopts the Topology of a Phylogenetic Tree 总被引:6,自引:0,他引:6
We propose a new type of unsupervised, growing, self-organizing neural network that expands itself by following the taxonomic
relationships that exist among the sequences being classified. The binary tree topology of this neutral network, contrary
to other more classical neural network topologies, permits an efficient classification of sequences. The growing nature of
this procedure allows to stop it at the desired taxonomic level without the necessity of waiting until a complete phylogenetic
tree is produced. This novel approach presents a number of other interesting properties, such as a time for convergence which
is, approximately, a lineal function of the number of sequences. Computer simulation and a real example show that the algorithm
accurately finds the phylogenetic tree that relates the data. All this makes the neural network presented here an excellent
tool for phylogenetic analysis of a large number of sequences.
Received: 14 May 1996 / Accepted: 6 August 1996 相似文献
15.
When human T cell receptor for antigen (TCR) alpha chain V-genes were compared pair-wise, the numbers of nucleotide differences
showed a characteristic distribution; most were in the range of 100 to 200 differences out of a total of about 300 bases.
The same distribution was observed for mouse TCR alpha chains. Even more interesting was that comparing human alpha chains
and mouse alpha chains gave essentially the same nucleotide difference pattern. It is inferred from the large number of differences
and from the nonspecificity of trans-species (human and mouse) nucleotide sequence differences of TCR V-genes that TCR alpha
chains probably diverged early during evolution. The same feature was also observed for human and mouse TCR beta chains, although
the alpha and beta chain V-genes were distinct. This evolutionary preservation could be of vital importance to the fidelity
of the complicated trimolecular interactions among TCR alpha and beta chains, the processed peptide, and the major histocompatibility
complex (MHC) class I or II molecules.
Received: 22 January 1996 / Accepted: 9 September 1996 相似文献
16.
Elizaveta V. Benevolenskaya Galina L. Kogan Alexey V. Tulin Dominik Philipp Vladimir A. Gvozdev 《Journal of molecular evolution》1997,44(6):646-651
The peculiarities of the sequences of 18S rDNA included in a 90-kb DNA segment cloned in YAC vector are described. This heterochromatic
segment is situated on the X chromosome distal to the main rDNA cluster. The pseudo 18S rDNA sequence comprised undamaged
stretches of rDNA interspersed with segments characterized by high density of nucleotide substitutions and insertions/deletions.
The observed patchwork arrangement of unaltered rDNA sequences was considered as evidence of segmented gene conversion events
between the normal and damaged genes which are thought to constitute one of the mechanisms of rDNA array homogenization. The
18S rDNA fragment (510 bp) located nearby, homologous to the internal, undamaged part of pseudo 18S rDNA, carries comparable
density of randomly distributed nucleotide substitutions with no evidence of correction.
Received: 8 August 1996 / Accepted: 7 December 1996 相似文献
17.
Charles Lee Dean R. Court Charles Cho Jennifer L. Haslett Chyi-Chyang Lin 《Journal of molecular evolution》1997,44(3):327-335
Based on sequence analyses of 17 complete centromeric DNA monomers from ten different deer species, a model is proposed for
the genesis, evolution, and genomic organization of cervid satellite I DNA. All cervid satellite I DNA arose from the initial
amplification of a 31-bp DNA sequence. These 31-bp subrepeats were organized in a hierarchical fashion as 0.8-kb monomers
in plesiometacarpalia deer and 1-kb monomers in telemetacarpalia deer. The higher-order repeat nature of cervid centromeric
satellite DNA monomers accounts for their high intragenomic and intraspecific sequence conservation. Such high intraspecific
sequence conservation validates the use of a single cervid satellite I DNA monomer from each deer species for interspecific
sequence comparisons to elucidate phylogenetic relationships. Also, a specific 0.18-kb tandem duplication was observed in
all 1-kb monomers, implying that 1-kb cervid satellite I DNA monomers arose from an unequal crossover event between two similar
0.8-kb ancestral DNA sequences.
Received: 28 May 1996 / Accepted: 24 October 1996 相似文献
18.
The yeast Peptide Sensitive Channel (PSC), a cationic channel of the mitochondrial outer membrane closes with slow kinetics
at potentials of either polarity. The properties of this inactivation closely resemble those of the Voltage-Dependent Anion
Channel (VDAC) slow kinetics closures. Addition of trypsin to one compartment suppresses the inactivation observed when this
compartment is made positive, but does not affect the inactivation observed at potentials of reverse polarity. Both sides
of the channel are sensitive. The reduced form of the Mast Cell Degranulating peptide (rMCD) increases the rate of inactivation,
but only when the polarity of the compartment to which it is added is positive. The effect is not reversed by washing the
peptide out, but is suppressed by trypsin. The peptide can bind to both sides of the membrane. The effect of rMCD on PSC closely
resembles that of the ``modulator' on VDAC. The similarities between PSC and VDAC suggest that the former might be a cationic
porin of the mitochondrial outer membrane possessing a structure closely related to that of VDAC.
Received: 2 February 1996/Revised: 18 October 1996 相似文献
19.
Fusion of Human Sperm to Prostasomes at Acidic pH 总被引:9,自引:0,他引:9
Prostasomes are membranous vesicles (150–200 nm diameter) present in human semen. They are secreted by the prostate and contain
large amounts of cholesterol, sphingomyelin and Ca2+. In addition, some of their proteins are enzymes. Prostasomes enhance the motility of ejaculated spermatozoa and are involved
in a number of additional biological functions. The possibility that they may fuse to sperm has never been proved. In this
work, we studied the fusion of sperm to prostasomes by using various methods (relief of octadecyl Rhodamine B fluorescence
self-quenching, fluorescence microscopy and flow cytometry) and we found that it occurs at acidic pH (4–5), but not at pH
7.5 pH-dependent fusion relies on the integrity of one or more proteins and is different from the Ca2+-stimulated fusion between rat liver liposomes and spermatozoa that does not require any protein and occurs at neutral pH.
We think that the H+-dependent fusion of prostasomes to sperm may have physiological importance by modifying the lipid and protein pattern of
sperm membranes.
Received: 19 June 1996/Revised: 4 September 1996 相似文献
20.
Ivan Laprevotte Sophie Brouillet Christophe Terzian Alain Hénaut 《Journal of molecular evolution》1997,44(2):214-225
A computer-assisted analysis was made of 24 complete nucleotide sequences selected from the vertebrate retroviruses to represent
the ten viral groups. The conclusions of this analysis extend and strengthen the previously made hypothesis on the Moloney
murine leukemia virus: The evolution of the nucleotide sequence appears to have occurred mainly through at least three overlapping
levels of duplication: (1) The distributions of overrepresented (3–6)-mers are consistent with the universal rule of a trend
toward TG/CT excess and with the persistence of a certain degree of symmetry between the two strands of DNA. This suggests
one or several original tandemly repeated sequences and some inverted duplications. (2) The existence of two general core
consensuses at the level of these (3–6)-mers supports the hypothesis of a common evolutionary origin of vertebrate retroviruses.
Consensuses more specific to certain sequences are compatible with phylogenetic trees established independently. The consensuses
could correspond to intermediary evolutionary stages. (3) Most of the (3–6)-mers with a significantly higher than average
frequency appear to be internally repeated (with monomeric or oligomeric internal iterations) and seem to be at least partly
the cause of the bias observed by other researchers at the level of retroviral nucleotide composition. They suggest a third
evolutionary stage by slippage-like stepwise local duplications.
Received: 3 January 1996 / Accepted: 27 March 1996 相似文献