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.     

Crystallographic data for a penicillin receptor : exocellular DD-carboxypeptidase-transpeptidase from Streptomyces R61.

A pencillin-sensitive enzyme, the exocellular dd-carboxypeptidase-transpeptidase from Streptomyces R61, has been crystallized from polyethylene glycol (M_r = 6000 to 7500) solution at pH 7·6. X-ray examination of the orthorhombic crystals shows the space group is P2₁2₁2₁, with unit cell dimensions $\text{a = 51·1}\text{A}\text{?}\text{, b = 67·4}\text{A}\text{?}\text{,}\text{and}\text{c = 102·9}\text{A}\text{?}$. With four molecules of molecular weight 38,000, the $\text{A}\text{?}{}^3\text{/}\text{dalton}$ ratio for the cell is 2·33. The crystals are stable to irradiation for 75 hours and are suitable for structure analysis to at least 2·4 Å resolution. The radius of gyration of the molecule in solution at pH 6.8 is 20.8 Å.     

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.     

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.     

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.     

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.     

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.     

Crystallization of hen eggwhite riboflavin-binding protein

Crystals of hen eggwhite riboflavin-binding protein have been grown by equilibrium dialysis in solutions buffered with 0.05 m-Tris · HCl (pH 8.5) using ammonium sulphate as the precipitant. The crystals belong to the space group P3₁21 (or enantiomorph) with $\text{a = b = 112.5}\text{A}\text{?}\text{and}\text{c = 72.0}\text{A}\text{?}\text{,}$ and diffract to a resolution of 2.8 Å.     

Preliminary studies of crystals of poliovirus type I

Poliovirus contains 60 copies each of four coat protein subunits arranged on a T = 1 icosahedral surface. Crystals of the Mahoney and the Sabin strains of the type I serotype of polio have been obtained. Crystals of the Mahoney strain belong to the orthorhombic space group P2₁2₁2 with $\text{a = 324}\text{A}\text{?}\text{, b = 359}\text{A}\text{?}\text{, c = 381}\text{A}\text{?}$, contain $\text{1}\text{2}$ virus particle in the asymmetric unit, and diffract to at least 2.5 Å resolution. The crystals are apparently identical to those characterized by Finch & Klug (1959). Collection of three-dimensional X-ray diffraction data to 2.9 Å resolution is in progress.     

Crystallographic study of the iron-sulfur flavoprotein trimethylamine dehydrogenase from the bacterium W3A1

Large single crystals of trimethylamine dehydrogenase, containing both [4Fe-4S]²⁺ centers and covalently bound FMN, have been prepared by the macro seeding technique. The crystals are monoclinic, space group P2₁ with cell parameters $\text{a = 147.63}\text{A}\text{?}\text{, b = 71.96}\text{A}\text{?}\text{, c = 83.66}\text{A}\text{?}\text{and}\text{β = 97.64 °}$, and diffract to at least 2.0 Å resolution. There is one dimer of approximately 166,000 M_m per asymmetric unit. A 5.0 Å resolution anomalous scattering difference Patterson has been computed which shows the presence and position of two [4Fe-4S]²⁺ centers in the asymmetric unit. A self-rotation function computed at 6.0 Å resolution indicates a non-crystallographic 2-fold axis relating the two subunits. These results show trimethylamine dehydrogenase to be composed of two identical or very similar subunits each containing one [4Fe-4S]²⁺ center.     

Crystallization of alfalfa mosaic virus coat protein as a T = 1 aggregate

Reassembled alfalfa mosaic virus coat protein was partially digested with trypsin to remove the first 26 amino acids (Bol et al., 1974). These particles are empty icosahedral protein shells built with 60 alfalfa mosaic virus protein subunits. This aggregate has been crystallized in two different crystal forms, one of which diffracts X-rays to at least 3.4 Å resolution. The type I crystals (space group $\text{P6}{}_3\text{, a = 200}\text{A}\text{?}\text{, c = 314}\text{A}\text{?}$) contain two particles per cell separated by 195 Å with each sitting on a 3-fold axis. The type II crystals contain three particles per cell in space group P3₁or P3₂ ($\text{a = 201}\text{A}\text{?}\text{, c = 485}\text{A}\text{?}$). Other T = 1 viral particles have very similar diameters.     

Highly ordered crystals of the plant seed protein crambin.

Crystals of crambin, a plant seed protein of molecular weight 5000, diffract X-rays strongly to the interplanar spacing limit of 0.88 Å. These diffraction data should allow a definition of atomic structure that is on a par with that typically obtained from crystals of small organic molecules. The crystals are in space group P2₁ and have unit cell dimensions $\text{a = 41.1}\text{A}\text{?}\text{, b = 18.7}\text{A}\text{?}\text{, c = 22·7}\text{A}\text{?}\text{,}\text{and}\text{β = 90.6 °}$. The asymmetric unit contains one protein molecule.     

Letter: Preliminary crystallographic data for Escherichia coli beta-lactamase

The β-lactamase (penicillinase) from Escherichia coli W3310 has been crystallized from 25% saturated ammonium sulfate solution at pH 6.9. An X-ray examination of the monoclinic crystals shows the space group is C2, with unit cell dimensions $\text{a = 47.2}\text{A}\text{?}$, $\text{b = 76.9}\text{A}\text{?}$, $\text{c = 73.3}\text{A}\text{?}$ and β = 98.6°. With Z = 4 and the molecular weight = 22,000 (Melling &; Scott, 1972), the ų/dalton ratio is 2.98. The crystals are suitable for structure analysis to at least 2.4 Å resolution.     

Preliminary X-ray studies on Pseudomonas isoamylase

Single crystals of Pseudomonas isoamylase (M_r 95,000) belong to space group P2₁2₁2₁ with unit cell dimensions of $\text{a = 137.9}\text{A}\text{?}\text{, b = 52.9}\text{A}\text{?}\text{, c = 151.2}\text{A}\text{?}$. A Guinier plot of the X-ray small-angle scattering of the protein solution gave the radius of gyration of the molecule as 27.5 Å.     

Crystallization of and preliminary X-ray diffraction data for TET-repressor and the TET-repressor-tetracycline complex

The TET-repressor encoded by the transposon Tn10 has been crystallized along with the repressor-tetracycline complex. Both crystals belong to the space group P4₃2₁2 (or P4₁2₁2) with cell dimensions $\text{a = b = 74.3(1)}\text{A}\text{?}\text{, c = 94.2(2)}\text{A}\text{?}\text{and}\text{a = b = 73.3(1)}\text{A}\text{?}\text{, c = 94.6(2)}\text{A}\text{?}$ for the free and complexed repressor, respectively. There is one molecule of molecular weight 23,000 per asymmetric unit, and the biologically active dimer therefore consists of two identically formed subunits which are related by a crystallographic 2-fold axis. This isomorphism of TET-repressor and its tetracycline complex suggests that only minor, subtle changes in structure trigger binding to or release of the operator. The crystals of the native protein permit X-ray data collection to 3.2 Å and those of the complexed repressor to 2.8 Å.     

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.     

Preliminary x-ray diffraction studies on the "goose-type" lysozyme from the egg-white of the black swan Cygnus atratus

The “goose-type” lysozyme isolated from the egg-white of the black swan Cygnus atratus has been crystallized. The space group is P2₁ with one molecule of protein in the asymmetric unit. The cell parameters are $\text{a = 46.2}\text{A}\text{?}\text{, b = 65.1}\text{A}\text{?}\text{, c = 38.7}\text{A}\text{?}$, β = 110 °. The crystals diffract to a resolution of 2.25 Å and a set of diffraction data for the native protein has been collected photographically.     

Crystallization of 5-enolpyruvylshikimate 3-phosphate synthase from Escherichia coli

Crystals of 5-enolpyruvylshikimate 3-phosphate synthase from Escherichia coli have been grown out of ammonium sulfate by the hanging drop method of vapor diffusion. The crystals belong to the hexagonal space group P6₁22 or P6₅22, with $\text{a = 124}\text{A}\text{?}\text{and}\text{c = 381}\text{A}\text{?}$, and diffract to 3.8 Å resolution.     

Preliminary X-ray crystallographic study of the turkey lens protein, δ-crystallin

The structural protein, δ-crystallin, has been purified and crystallized from adult turkey lens. The crystals are orthorhombic and normally belong to space group P2₁2₁2 with unit cell dimensions $\text{a = 99.9(2)}\text{A}\text{?}\text{, b = 133.4(3)}\text{A}\text{?}\text{and}\text{c = 69.1(2)}\text{A}\text{?}$. This corresponds to two molecules of molecular weight approximately 200,000 per unit cell. A second crystal form has also been found in which b and c increase to 135.4(3) Å and 140.0(3) Å. respectively, indicating four molecules per unit cell.