On the DNA binding protein II from Bacillus stearothermophilus. I. Purification, studies in solution, and crystallization

DNA binding protein II from Bacillus stearothermophilus has been purified as a single species from the nonribosomal cell fraction by a combination of gel filtration and ion exchange chromatography. The protein occurs in solution as a tetramer and is able to bind to 30 S, 50 S, and 70 S ribosomal particles. Circular dichroism studies show that the protein has approximately 45% alpha-helix. The secondary structure of the Bacillus protein is considerably more resistant to the effects of increasing temperature and urea concentration than the homologous protein (NS1 and NS2) from Escherichia coli. Proton magnetic resonance experiments show that the protein has a well folded, compact tertiary structure. The DNA binding protein has been crystallized from several precipitants as monoclinic needles and triclinic plates. The monoclinic form diffracts to at least 3.5 A and oscillation data from the native crystals have been collected. The protein is able to bind to both single- and double-stranded oligodeoxyribonucleotides. Upon binding, several changes occur in the protein NMR spectrum which may be used for further analysis of the mechanism of interaction.     

Isolation of a plasma protein elevated during hypertension in the rat

Plasma from male rats contains a protein that is elevated during essential hypertension. This protein, termed hypertension associated protein (HAP), can be detected as a peptide that has a molecular weight of 14,000 daltons on high resolution SDS-gradient polyacrylamide gels. The native protein has now been isolated by elution from DEAE-Sepharose, carboxymethyl cellulose and by gel permeation on Ultrogel AcA44. The procedure yields 102 mg of highly purified protein from 5 ml (250 mg) of plasma in 72 h. The native protein has a molecular weight of 28,000 daltons.     

Purification and reconstitution into liposomes of an integral membrane protein conferring immunity to colicin A

Abstract The immunity protein to colicin A protects producing cells from the action of this pore-forming toxin. It is located into the cytoplasmic membrane. This protein has been 'tagged' with an epitope from the colicin A protein for which a monoclonal antibody is available. The fusion protein (named VL1) has been purified after extraction from the membrane in two steps using a chromatofocusing and an immunoadsorbant chromatography. The purified protein has then been reconstituted into lipid vesicles.     

Some properties of phosphatidylcholine exchange protein purified from beef liver

A phospholipid exchange protein has been purified 2680-fold from beef liver. The assay of the exchange activity of the protein was based on the transfer of [¹⁴C]phosphatidylcholine from microsomes labeled with [¹⁴C]phosphatidylcholine to liposomes. The homogeneity of the protein has been established by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, immunoelectrophoresis and isoelectric focusing. The protein has a molecular weight of approximately 22000 and an isoelectric point of 5.8. The amino acid composition has been determined. The protein contains one disulfide bridge and has glutamic acid as the N-terminal amino acid. Phospholipid, tentatively identified as phosphatidylcholine, was found to be present in the protein preparation. The protein stimulated specifically the exchange of phosphatidylcholine between mitochondria and microsomes from rat liver.     

准噶尔小胸鳖甲抗冻蛋白基因Mpafp149的生物信息学分析

利用生物信息学方法对准噶尔小胸鳖甲抗冻蛋白基因Mpafp149所编码蛋白MPAFP149进行分析,分别从氨基酸组成、理化性质、二三级结构和功能、进化关系等方面进行预测。结果表明MPAFP149与其他昆虫抗冻蛋白在氨基酸水平上具有79％的相似性,二级结构上预测其为水溶性蛋白,含有信号肽和跨膜区。三级结构上与黄粉虫抗冻蛋白YL-1具有较高的相似性,并且具有昆虫抗冻蛋白所特有的结构域。本研究为准噶尔小胸鳖甲抗冻蛋白功能的研究鉴定了基础。     

Purification and sequence determination of a yellow protein from sexually mature males of the desert locust, Schistocerca gregaria

A yellow protein from abdominal cuticle of the desert locust, Schistocerca gregaria, has been purified and its amino acid sequence determined. The yellow color comes from bound carotene, the protein is only deposited in the epidermis and cuticle of male locusts during their sexual maturation, and the deposition is dependent upon a sufficiently high titer of juvenile hormone. The sequence of the protein is atypical for a cuticular protein, but it has some similarity to a putative juvenile hormone binding protein from Manduca sexta. It is suggested that the protein is involved in the transport of carotenes from internal tissues to epidermis and cuticle of the locust.     

Isolation and characterization of Ca2+-dependent modulator protein from the marine invertebrate Renilla reniformis.

An acidic, low molecular weight (18 400--19 100) protein capable of activating porcine brain phosphodiesterase in the presence of calcium has been purified 2700-fold from the anthozoan coelenterate, Renilla reniformis. The protein has physical, spectral, and chemical properties similar to those of modulator proteins isolated from mammalian species. Amino acid composition studies reveal no significant differences between the Renilla and mammalian modulator proteins. For example, we observed 1 mol of epsilon-N-trimethyllysine per mol of protein, no tryptophan or cysteine, and high levels of glutamic and aspartic acid residues. The protein from Renilla complexes with troponin I and T subunits in the presence of calcium and quantitatively replaces porcine brain modulator in the calcium-dependent activation of porcine brain phosphodiesterase. The protein has a high affinity for calcium as judged by the low levels of free calcium required for modulator-dependent activation of phosphodiesterase. The similarities in physical and chemical properties, high affinity for calcium, and identical calcium-dependent activities of this protein from Renilla (as compared with modulator protein purified from mammalian systems) suggest that a high degree of structural conservation has been retained in modulator proteins isolated from these diverse evolutionary forms.     

Radioimmunoassay for a vitamin-d dependent calcium-binding protein in rat duodenal mucosa

A radioimmunoassay for a vitamin D-stimulated calciumbinding protein from rat intestine has been developed. The assay can measure as little as 0.5 ng protein and has allowed to detect an immunoreactive material in rat serum. On the other hand, no cross-reactivity has been observed with either the protein from rat kidney or that from pig duodenum.     

The complete amino-acid sequence of dimeric beta-lactoglobulin from mouflon (Ovis ammon musimon) milk

beta-Lactoglobulin from Mouflon (Ovis ammon musimon) milk has been isolated and its complete primary structure determined. This protein has been isolated in dimeric form and has a molecular mass of 37 kDa. The amino-acid sequence has been determined by microsequencing of the native protein and the peptides were obtained after tryptic cleavage. The tryptic peptides were isolated by reversed phase high-performance liquid chromatography. The primary structure of mouflon beta-lactoglobulin shows close similarity to ruminant beta-lactoglobulins. The presence of His at position 20 indicates that this protein belongs to the B-type of dimeric ovine beta-lactoglobulins. Mouflon beta-lactoglobulin is a 162 amino acid long polypeptide chain with two disulphide bridges and one free thiol group. Structural similarities to the bilin-binding protein, BG protein from olfactory epithelium and retinol-binding protein are discussed.     

Purification and characterization of a spinach-leaf protein capable of transferring phospholipids from liposomes to mitochondria or chloroplasts

A phospholipid transfer protein has been purified 195-fold from an extract of spinach leaves. This protein is capable of transferring phosphatidylcholine, phosphatidylinositol, phosphatidylglycerol and phosphatidylethanolamine from liposomes to mitochondria. In addition to this protein, a minor part of the total activity was associated with a less purified fraction. The pure protein has an isoelectric point of 9.0 +/- 0.2 determined by a chromatofocusing technique. Electrophoresis on sodium dodecyl sulfate/polyacrylamide gel showed that the protein is homogeneous and has an apparent molecular weight of 9000 +/- 1000, in agreement with the value (8832) calculated from the amino acid composition. This composition is characterized by a high amount of alanine and glycine and by the absence of phenylalanine, whereas arginine, glutamine, histidine and methionine are minor components. The spinach protein is also able to transfer phosphatidylcholine and phosphatidylglycerol from liposomes to intact chloroplasts. This observation reinforces the hypothesis that plastid phospholipids are partly imported from outside the organelle by a transfer process.     

Retinoic acid-binding protein in rat tissue. Partial purification and comparison to rat tissue retinol-binding protein.

When the 100,000 X g supernatant fractions of several rat organs are incubated with all-trans-[3H]retinoic acid, a binding component for retinoic acid with a sedimentation coefficient of 2 S can be detected by sucrose gradient centrifugation. This tissue binding protein for retinoic acid is distinct from the tissue binding protein for retinol which has been previously described. The tissue retinoic acid-binding protein has been partially purified from rat testis and this partially purified protein would appear to have a molecular weight of 14,500 as determined by gel filtration and high binding specificity for all-trans-retinoic acid. Binding of [3H]retinoic acid is not diminished by a 200-fold molar excess of retinal, retinol, or oleic acid but is reduced by a 200-fold excess of unlabeled retinoic acid. Tissue retinoic acid-binding protein can be detected in extracts of brain, eye, ovary, testis, and uterus but is apparently absent in heart muscle, small intestine, kidney, liver, lung, gastrocnemious muscle, serum, and spleen. This distribution is different than that observed for the tissue retinol-binding protein. Tissue retinol-binding protein was also purified extensively from rat testis. The partially purified protein has an apparent molecular weight of 14,000 and high binding specificity for all-trans-[3H]retinol as only unlabeled all-trans-retinol but not retinal, retinoic acid, retinyl acetate, retinyl palmitate, or oleic acid could diminish binding of the 3H ligand under the conditions employed. The partially purified protein has a fluorescence excitation spectrum with lambda max at 350 nm. In contrast, the retinol-binding protein isolated from rat serum and described by others has a fluorescence excitation spectrum with lambda max at 334 nm and an apparent molecular weight of 19,000. When partially purified tissue retinol-binding protein is extracted with heptane, the heptane extract has a fluorescence excitation spectrum similar to that of all-trans-retinol.     

Matrix Gla protein, a new gamma-carboxyglutamic acid-containing protein which is associated with the organic matrix of bone

A new protein has been isolated from CaCl2/urea extracts of demineralized bovine bone matrix. This protein has five to six residues of the vitamin K-dependent amino acid, gamma-carboxyglutamic acid (Gla), and we have accordingly designated it matrix Gla protein. Matrix Gla protein is a 15,000 dalton protein whose amino acid composition includes a single disulfide bond. The absence of 4-hydroxyproline in matrix Gla protein demonstrates that it is not a precursor to bone Gla protein, 5,800 dalton protein which has a residue of 4-hydroxyproline at position 9 in its sequence. Matrix Gla protein also does not cross-react with antibodies raised against bone Gla protein.     

Diversity of the outer membrane protein P2 gene from major clones of Haemophilus influenzae type b

In previous studies, it has been demonstrated that outer membrane protein P2 from Haemophilus influenzae type b has porin activity and that antibody directed against P2 is protective in an infant rat bacteraemic model. Outer membrane protein subtyping has been employed to subclassify type b Haemophilus isolates. Strain MinnA has the outer membrane protein subtype 1H and is representative of the dominant clonal group of disease-producing isolates in the United States. In the present study, the P2 gene from strain MinnA was employed to probe EcoRI- and Pvull-digested chromosomal DNA from 24 Haemophilus influenzae type b isolates representative of the common outer membrane protein subtype groups observed throughout the world. Restriction fragment length polymorphisms were identified for the members of the outer membrane protein subtype 3L group, but not for the other subtypes examined. The P2 gene from each of four prototype isolates was then cloned, sequenced and compared to the previously reported sequence of the strain MinnA gene. The P2 gene from each of two isolates with the outer membrane protein subtype 3L was identical to the MinnA P2 sequence. The P2 gene from a subtype 2L isolate differed by a single nucleotide and the gene from a subtype 6U isolate differed by 13 nucleotides. Thus, the P2 protein is highly conserved among type b isolates.     

Regulation of transmethylation by an S-adenosylmethionine binding protein

A protein which has a high affinity for S-adenosylmethionine (SAM) has been partially purified from rat liver. This binding protein stimulates both the rate and extent of product formation when added to both a lipid methylating system, phosphatidylethanolamine: SAM-N-methyltransferase, and an RNA methylating system, the t-RNA methylase complex from rat liver. The S-adenosylmethionine binding protein by itself has no enzymatic activity in either transmethylation system.     

ATP synthase from bovine mitochondria: complementary DNA sequence of the import precursor of a heart isoform of the alpha subunit

The alpha-subunit of ATP synthase from mitochondria is a major component of the extrinsic membrane sector of the enzyme. It is encoded in nuclear DNA. A family of overlapping complementary DNA clones encoding its precursor has been isolated from a bovine library by using in the first instance a mixture of 128 synthetic oligonucleotides designed on the basis of the known protein sequence, and the sequence of the full-length cDNA has been determined. The deduced protein sequence shows that the alpha-subunit of ATP synthase has a presequence of 43 amino acids that is not present in the mature protein. Presumably it directs the protein into the mitochondrial matrix and is removed during the import process. The encoded protein sequence is also longer by one amino acid at its C-terminal end than the protein isolated from F1-ATPase, but this alanine residue may have been removed artifactually during release of the F1-ATPase particle from the inner mitochondrial membrane. With the exception of one uncertainty caused by an ambiguity at one position in the nucleotide sequence, the mature protein sequence encoded in the cDNA is exactly the same as the sequence determined previously by direct analysis of the protein isolated from bovine heart mitochondria [Walker et al. (1985) J. Mol. Biol. 184, 677-701]. The cDNA sequence differs in 158 nucleotides over a region of alignment of 1097 nucleotides from a partial cDNA for the alpha-subunit that has been isolated from a bovine cDNA derived from liver RNA [Breen (1988) Biochem. Biophys. Res. Commun. 152, 264-269].(ABSTRACT TRUNCATED AT 250 WORDS)     

Shark Myelin Basic Protein: Amino Acid Sequence, Secondary Structure, and Self-Association

Myelin basic protein (MBP) from the Whaler shark (Carcharhinus obscurus) has been purified from acid extracts of a chloroform/methanol pellet from whole brains. The amino acid sequence of the majority of the protein has been determined and compared with the sequences of other MBPs. The shark protein has only 44% homology with the bovine protein, but, in common with other MBPs, it has basic residues distributed throughout the sequence and no extensive segments that are predicted to have an ordered secondary structure in solution. Shark MBP lacks the triproline sequence previously postulated to form a hairpin bend in the molecule. The region containing the putative consensus sequence for encephalitogenicity in the guinea pig contains several substitutions, thus accounting for the lack of activity of the shark protein. Studies of the secondary structure and self-association have shown that shark MBP possesses solution properties similar to those of the bovine protein, despite the extensive differences in primary structure.     

The gamma protein specified by bacteriophage gamma. Structure and inhibitory activity for the recBC enzyme of Escherichia coli.

The protein encoded by the gam gene of bacteriophage lambda ("gamma protein") is a specific inhibitor of the recBC enzyme of Escherichia coli. The lambda protein has been purified approximately 2,000-fold, and its structure and inhibitory activity have been characterized. It appears to be composed of two identical subunits of 16,500 daltons, inhibits all of the catalytic activities of the recBC enzyme with apparently equal efficiency, but has no effect upon any other E. coli or lambda-DNase tested. Inhibition does not occur unless recBC enzyme is exposed to gamma protein prior to reaction of the enzyme with DNA. The inhibitory activity is independent of temperature, and no catalytic activity has been detected that might fulfill the inhibitory function. It appears instead that the inhibition involves a stoichiometric, rather than a catalytic interaction between gamma protein and the enzyme. Reaction kinetics for the recBC enzyme inhibited by gamma protein show no anomalous protein--only a depressed rate. Inhibition is not competitive and does not appear to affect the enzyme's affinity for DNA. The enzyme remains inhibited after it is separated from "excess" gamma protein by gel filtration or sedimentation in a glycerol gradient, and inhibited enzyme has a reduced electrophoretic mobility compared to that of uninhibited enzyme. Gamma Protein inhibits recBC enzyme which has been reconstituted from cell-free extracts by complementation in vitro, but at least one of the complementing factors present in extracts from recB- cells does not by itself form a complex with gamma protein. The mechanism of inhibition and the implications of these results from gamma replication and recombination are discussed.     

Colchicine-binding protein from phloem and xylem of a higher plant

Summary Colchicine has been demonstrated by ion-exchange and by gelfiltration assay to bind to a protein fraction derived from the higher plant Heracleum mantegazzianum. Colchicine-binding protein from a plant source was much more unstable than tubulin from animal preparations. The tissues of Heracleum vary in their content of colchicine-binding activity. No activity was obtained from non-vascular tissue. Phloem has at most, twice as much activity as xylem. The significance of these results is discussed in relation to a proposed degree of homology between P protein of phloem and microtubule protein.     

The primary structure of rat ribosomal protein L7. The presence near the amino terminus of L7 of five tandem repeats of a sequence of 12 amino acids

The covalent structure of rat ribosomal protein L7 was determined in part from the sequence of nucleotides in a recombinant cDNA and in part from the sequence of amino acids in portions of the protein. The complementary analyses supplemented and confirmed each other. Ribosomal protein L7 contains 258 amino acids and has a molecular weight of 30,040. The protein has an unusual and striking structural feature near the NH2 terminus: five tandem repeats of a sequence of 12 residues. Rat L7 appears to be related to ribosomal protein L7 from the moderate halophile Vibrio costicola and perhaps to L30 from Bacillus stearothermophilus, to L7 from the moderate halophile NRCC 41227, and to L22 from Nicotinia tobaccum chloroplast. In addition, there is a sequence of 24 amino acids in rat protein L7 that may be related to segments of the same number of residues in Escherichia coli ribosomal proteins S10, S15, L9, and L22.