A lysosomal factor that interconverts multiple forms of rat liver tyrosine aminotransferase.

A particulate factor of rat liver is described which interconverts three forms of rat liver cytosolic tyrosine aminotransferase $\text{in}$$\text{vitro}$ with no alteration of enzyme activity. The factor appears to be a heat- and pH-sensitive lysosomal protein. The interconversion process is stimulated $\text{in}$$\text{vitro}$ by 2.5 mM MgCl₂ and 2.5 mM ATP. Asparate aminotransferase multiple forms are also susceptible to $\text{in}$$\text{vitro}$ interconversion by the lysosomal factor. The properties of the factor explain several anomalous effects of $\text{in}$$\text{vitro}$ manipulation on the tyrosine aminotransferase forms which have been reported in the literature and implicate the form interconversion in the degradation of tyrosine aminotransferase.     

Crystallographic study of beef liver catalase

An orthorhombic form of beef liver catalase crystals has been examined by X-ray diffraction and electron microscopy. The space group is P2₁2₁2₁ with $\text{a = 89}\text{A}\text{?}\text{, b = 140}\text{A}\text{?}\text{, and}\text{c = 231}\text{A}\text{?}$. Electron micrographs show the presence of broad channels arrayed in a hexagonal manner. The solvent content of these orthorhombic crystals is considerably less than that for previously reported trigonal crystals of beef liver catalase although the packing arrangement appears to be virtually the same, suggesting a possible symmetry transition upon dehydration.     

Crystallographic analysis of the phytoagglutinin from Abrus precatorius by X-ray diffraction and electron microscopy

The lectin from the seeds of Abrus precatorius has been crystallized and the crystals subjected to study by X-ray diffraction and electron microscopy. Three closely related crystal forms were obtained, of orthorhombic space group P2₁2₁2₁ with $\text{a = 138}\text{A}\text{?}$, $\text{b = 142}\text{A}\text{?}$, and $\text{c = 173}\text{A}\text{?}$, of tetragonal space group P4₁2₁2 with $\text{a = b = 136}\text{A}\text{?}$, $\text{c = 176}\text{A}\text{?}$, and a twinned intermediate of the first two. From electron microscopy and two-dimensional spatial filtering of electron micrographs of the crystals, the molecule appears to consist of four similar domains grouped in a roughly planar diamond-shaped arrangement having a local intramolecular dyad axis. The average diameter of the Abrus lectin molecule is 50 to 60 Å and the individual domains appear to have a diameter of about 25 Å.     

Crystallographic studies on concanavalin B

Concanavalin B has been grown as hexagonal needles and analyzed by x-ray diffraction and electron microscopy. The crystals are of space group P6₁ with $\text{a}$ = 81Å and $\text{c}$ = 101Å. There is one molecule of 30, 000 molecular weight as the asymmetric unit of the crystal. Electron micrographs demonstrate that the crystals maintain considerable order after dehydration and exhibit large intersticial solvent regions.     

Time resolved spectroscopy of the tryptophyl fluorescence of the E. coli LAC repressor.

A new crystal form of a mitogenic lectin from pea seeds ($\text{Pisum sativum}$) has been obtained which is suitable for high resolution structural work. The crystals are orthorhombic, space group P2₁2₁2₁, with unit cell dimensions: $\text{a}$ = 64.2Å, $\text{b}$ = 72. 7Å, $\text{c}$ = 108. 3Å. The asymmetric unit contains one protein molecule.     

A preliminary crystallographic study of isocitrate dehydrogenase from Azotobacter vinelandii

Large single crystals of isocitrate dehydrogenase from Azotobacter vinelandii have been grown by vapor diffusion from ammonium sulfate and phosphate solutions. The crystals are tetragonal, space group P4₂2₁2 with cell dimensions $\text{a = 122.1}\text{A}\text{?}$, $\text{c = 163.9}\text{a}\text{?}$. There are two molecules of 80,000 molecular weight per asymmetric unit. Native data to 5.5 Å resolution have been collected on a diffractometer. A rotation function using data between 10 Å and 6 Å resolution indicates three possible orientations of the non-crystallographic 2-fold axis relating the two molecules.     

Preliminary X-ray study of crystals of human transferrin

Large crystals of human transferrin have been grown from polyethylene glycol solutions. The crystals are orthorhombic, space group P2₁2₁2₁, with $\text{a = 78}\text{A}\text{?}\text{, b = 94}\text{A}\text{?}\text{and}\text{c = 112}\text{A}\text{?}$. Density measurements indicate that there are four transferrin molecules in the unit cell.     

Crystallization of the Arc repressor

Arc, a represser from Salmonella phage P22 has been crystallized from ammonium phosphate at pH 8.0. The crystals form in space group P2₁2₁2₁ with $\text{a = 90.26}\text{A}\text{?}\text{, b = 52.88}\text{A}\text{?}\text{and}\text{c = 47.58}\text{A}\text{?}$. The crystals diffract to 2.2 Å resolution.     

X-ray diffraction analysis of crystals of bovine platelet factor 4

Bovine platelet factor 4 has been crystallized by “vapor dilution” in space group P2₁2₁2₁, $\text{a = 63.7}\text{A}\text{?}\text{, b = 66.7}\text{A}\text{?}\text{, c = 80.5}\text{A}\text{?}$, with four molecules, each 9505 M_r, in the asymmetric unit. The crystals diffract X-rays to better than 2.8 Å resolution.     

Crystallization and preliminary x-ray investigation of ubiquitin, a non-histone chromosomal protein.

Large crystals of bovine thymus ubiquitin, a non-histone chromosomal protein, were grown from polyethylene glycol solutions. The crystals are orthorhombic, space group P2₁2₁2₁, with $\text{a = 50·9}\text{a}\text{?}\text{, b = 42·9}\text{A}\text{?}\text{and}\text{c = 29·0}\text{A}\text{?}$. The asymmetric unit contains one ubiquitin molecule.     

Preliminary crystallographic study of macromomycin: The apoprotein of the antitumor antibiotic auromomycin

Macromomycin (M_r 12,000) is the apoprotein of the antitumor drug auromomycin, which inhibits DNA synthesis by causing single-strand breaks in DNA. Two orthorhombic crystal forms of macromomycin have been observed. The platelike crystals of one form belong to space group P2₁2₁2₁, with cell dimensions $\text{a = 48·92}\text{A}\text{?}\text{, b = 54·71}\text{A}\text{?}\text{, c = 103·31}\text{A}\text{?}\text{, Z = 8}$. The crystals of the second form are needle-shaped, and belong to space group P2₁2₁2, with cell dimensions $\text{a = 46·1}\text{A}\text{?}\text{, b = 54·4}\text{A}\text{?}\text{, c = 41·2}\text{A}\text{?}\text{, Z = 4}$. At this point in time, the platelike crystals appear the most suitable for continued crystallographic studies.     

Crystallization of ribonuclease St

The crystals of ribonuclease St, the extracellular ribonuclease from Streptomyces erythreus, have been obtained from (NH₄)₂SO₄ solution with acetate buffer (pH 4.1). The crystals belong to a monoclinic space group C2 with dimensions $\text{a = 88.4}\text{A}\text{?}\text{, b = 33.0}\text{A}\text{?}\text{, c = 69.0}\text{A}\text{?}\text{, β = 98.4 °}$. There are two protein molecules per asymmetric unit. The crystals diffract beyond 2.0 Å resolution.     

A preliminary crystallographic study of β-glucuronidase from rat preputial gland

Large single crystals of rat preputial gland β-glucuronidase have been grown by dialysis against 2-methyl-2,4-pentanediol. The crystals are tetragonal, space group P4₁2₁2 or P4₃2₁2 with cell dimensions $\text{a = 103.5}\text{A}\text{?}\text{and}\text{c = 279.8}\text{A}\text{?}$. Each asymmetric unit contains one half of a tetramer composed of subunits of 69,000 molecular weight.     

Letter: Crystallization and preliminary x-ray diffraction studies on tyrosyl-transfer RNA synthetase from Bacillus stearothermophilus

Conditions have been established for the crystallization of tyrosyl-transfer RNA synthetase from Bacillus stearothermophilus at room temperature. The crystals are extremely well-ordered, exhibiting diffraction spots out to at least 2.7 Å, and can be grown to a convenient size for X-ray crystallographic analysis. The crystals are trigonal with a space group P3₁21, the unit cell having dimensions of $\text{a = 64.4}\text{A}\text{?}$ and $\text{c = 238}\text{A}\text{?}$; the crystallographic asymmetric unit is probably one subunit of the dimeric (2 × 45,000, mol. wt) enzyme. The enzyme crystals are extremely stable and exhibit good resistance to radiation damage. This amino-acyl-tRNA synthetase appears to be amenable to complete structure determination by X-ray crystallography.     

Characterization and preliminary crystallographic data on the VL-related fragment of the human kI Bence Jones protein Wat

A “naturally occurring” human κI V_L dimer, designated Wat, has been isolated and crystallized. Protein Wat consists of two non-covalently bound monomers, each having a molecular weight of ~ 11,500. The monomer subunit is composed of an entire variable region light chain (V_L) domain closely homologous to that of the κI Bence Jones protein Roy (Hilschmann &; Craig, 1965) as evidenced from amino acid composition, tryptic peptide map, and sequence analysis. Immunochemical studies substantiated that protein Wat is of the κ chain subgroup κI and lacks the isotypic and allotypic antigenic determinants associated with the κ constant region light chain domain. Two types of crystals of V_L dimer Wat were obtained from ammonium sulfate or polyethylene glycol solutions. The type I crystals have unit cell dimensions of $\text{a = b = 82.6}\text{A}\text{?}\text{, c = 60.3}\text{A}\text{?}$, and the space group is hexagonal P6₂ or P6₄. The asymmetric unit consists of one V_L dimer; the fractional volume of unit cell occupied by solvent is 0.51. The unit cell dimensions of the type II crystals are $\text{a = b = 1,08.3}\text{A}\text{?}\text{, c = 108.8}\text{A}\text{?}$; the space group is hexagonal P6₁22 or P6₅22. Three variable domains constitute the asymmetric unit of the type II crystals; the fractional value of the solvent (0.52) is compatible with the value obtained for the type I crystals.     

Opiate receptor affinities and behavioral effects of enkephalin: Structure-activity relationship of ten synthetic peptide analogues

Synthetic met- and leu-enkephalin bind to rat brain opiate receptors with $\text{1}\text{2}$ and $\text{1}\text{7}$ the affinity of morphine. The aromatic hydroxyl moiety of the tyrosine residue is critical for receptor binding. Intracranial microinjection of met-enkephalin requires very high doses to produce an evanescent, naloxone reversible analgesia and stuperous immobility, presumably because of its rapid enzymatic degradation. Leu-enkephalin fails to elicit analgesia.     

Crystallization and preliminary crystallographic data of rabbit uteroglobin

Uteroglobin is a steroid-binding protein of 15,800 molecular weight, composed of two chemically identical subunits which, in the oxidized form, are covalently linked by disulphide bridges. Large crystals have been grown from ammonium sulphate solutions by vapour diffusion as well as by equilibrium dialysis. The crystals are very stable under X-rays, diffract to at least 2.2 Å resolution and belong to space group P2₁. The unit cell, with dimensions $\text{a = 43.3}\text{A}\text{?}\text{, b = 31.1}\text{A}\text{?}\text{, c = 34.5}\text{A}\text{?}\text{, and}\text{β = 90.7 °}$, contains two dimeric molecules. The crystals exhibit a prominent pseudo symmetry corresponding to space group P2₁2₁2 which indicates that the two subunits should be structurally nearly identical.     

Characterization of lecithin:Cholesterol acyltransferase from human plasma: II. Physical properties of the enzyme

The physical properties of purified human plasma lecithin:cholesterol acyltransferase (LCAT) were investigated by techniques including analytical ultracentrifugation, ultraviolet spectroscopy, electrofocusing, and circular dichroism. The partial specific volume of LCAT was determined by sedimentation equilibrium ultracentrifugation experiments in H₂O and D₂O solutions (0.702 ml/g). The M_r was 67,000 by sodium dodecyl sulfate (SDS)-gel electrophoresis and 60,000 by sedimentation equilibrium ultracentrifugation. The discrepancy between the two sets of data presumably arose from the glycoprotein nature of the enzyme. Studies of the ultraviolet spectrum indicated that LCAT contained 6.5% ($\text{w}\text{w}$) tyrosine which corresponds to approximately 18 tyrosine residues/mol of LCAT (polypeptide M_r 45,000). Spectrophotometric titration of the ionizable phenolic side chains indicated that nearly all the tyrosine residues were buried at neutral pH while they became gradually exposed at higher pH. The apparent pK of this transition was about 12.0 contrasted with 9.8, the apparent pK of ionization of the free tyrosyl groups.     

Letter: Crystallographic data of an L-arabinose-binding protein from Escherichia coli

Single crystals of an l-arabinose-binding protein from Escherichia coli B/r suitable for a high-resolution structural analysis have been obtained. An X-ray examination of the orthorhombic crystals shows the space group is P2₁2₁2₁, with unit cell dimensions: $\text{a = 55.3}\text{A}\text{?}\text{, b = 71.4}\text{A}\text{?}\text{and}\text{c = 77.5}\text{A}\text{?}$. The asymmetric unit contains one protein molecule with a molecular weight of 38,000.     

Hydrophobic channels in crystals of an α-aminoisobutyric acid pentapeptide

The crystal structure of the pentapeptide p-toluene-sulfonyl-(α-aminoisobutyryl)₅-methyl ester (Tosyl-(Aib)₅-OMe) has been determined in the space group P$\text{I}$. Pentapeptide molecules are folded in the 3₁₀ helical conformation and packed together, so as to yield a hydrophobic channel with a minimim diameter of 5.2 Å. The channel contains crystallographically disordered material. This structure provides a model for channel formation by hydrophobic peptide aggregates and should prove useful in studies of alamethicin, suzukacillin and related Aib containing membrane channels. Triclinic (P$\text{I}$) crystals of the pentapeptide are obtained in the presence of LiClO₄ in aqueous methanol, whereas crystallization from methanol alone yields crystals in the space group Pbca. The conformations of the peptide in the two crystal forms are very similar and only the molecular packing is dramatically different.