Manganese superoxide dismutases from Escherichia coli and from yeast mitochondria: Preliminary X-ray crystallographic studies

The Mn superoxide dismutase from Escherichia coli has been obtained in three crystal forms: (I) from 68% saturated (NH₄)₂SO₄, space group P222 or P222₁, $\text{a = 47}\text{A}\text{?}\text{, b = 103}\text{A}\text{?}\text{, c = 47.5}\text{A}\text{?}$, with one subunit per asymmetric unit; (II) from 50% polyethylene glycol 6000, space group C222₁ (with approx. P4₁2₁2 symmetry), $\text{a = 101}\text{A}\text{?}\text{, b = 108}\text{A}\text{?}\text{, c = 180}\text{A}\text{?}$, with four subunits (2 molecules) per asymmetric unit; (III) from 52% polyethylene glycol with a different method of preparing the enzyme solution, space group P2₁2₁2, $\text{a = 47}\text{A}\text{?}\text{, b = 51}\text{A}\text{?}\text{, c = 188}\text{A}\text{?}$, with two subunits per asymmetric unit.The yeast mitochondrial Mn superoxide dismutase has yielded the same crystal form both from 30% 2-methyl-2,4-pentane diol and from 23% polyethylene glycol 6000: space group P2₁2₁2₁, $\text{a = 63}\text{A}\text{?}\text{, b = 115}\text{A}\text{?}\text{, c = 125}\text{A}\text{?}$, with four subunits (one molecule) per asymmetric unit.A full X-ray crystallographic study of at least one of these enzymes is planned.     

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.     

A preliminary crystallographic investigation of rabbit muscle creatine kinase

Three crystal forms of rabbit muscle creatine kinase have been grown, one of which seems suited to a high resolution X-ray diffraction study. The first form is of monoclinic space group P2₁ with $\text{a = 54}\text{A}\text{?}\text{, b = 114}\text{A}\text{?}\text{, c = 145}\text{A}\text{?}\text{, β = 91 °}$ and has as the asymmetric unit two molecules of total molecular weight 160, 000. The second form, grown in the presence of mercurials, is of space group A2 with $\text{a = 52}\text{A}\text{?}\text{, b = 165}\text{A}\text{?}\text{, c = 237}\text{A}\text{?}\text{, β = 91 °}$ and also has two molecules in the asymmetric unit. The third crystal form, grown in the presence of a high concentration of cysteine, is of apparent space group P2₁2₁2₁, but evidence indicates that the true space group may be P2₁22₁. The dimensions of the orthorhombic unit cell are $\text{a = 47}\text{A}\text{?}\text{, b = 86}\text{A}\text{?}\text{, c = 125}\text{A}\text{?}$, and the asymmetric unit contains a single protein subunit. Assuming the latter space group, then the creatine kinase molecule possesses a twofold axis relating two identical subunits.     

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.     

Characterization of two crystal forms of neutrophil cationic protein NP2, a naturally occurring broad-spectrum antimicrobial agent from leukocytes

A hexagonal crystal form (P6₃22, $\text{a = b = 34.0}\text{A}\text{?}\text{, c = 113.5}\text{A}\text{?}$) and a monoclinic form (P2₁, $\text{a = 37.1}\text{A}\text{?}\text{, b = 32.2}\text{A}\text{?}\text{, c = 32.4}\text{A}\text{?}\text{, β = 110 °}$) of neutrophil cationic protein NP2, isolated from rabbit leukocytes, have been characterized. The monoclinic form, containing two promoters (M_r = 3844) per asymmetric unit, diffracts to at least 1.8 Å and is suitable for high-resolution structural studies.     

Crystallography of Bacillus subtilis levansucrase

Levansucrase, an exocellular enzyme, has been isolated from a high producer mutant, the BS5C4 constitutive strain, of Bacillus subtilis. Three crystalline forms have been obtained, all three belonging to the orthorhombic space group P2₁2₁2₁. The most suitable form for a three-dimensional structure investigation has cell dimensions, $\text{a = 68}\text{A}\text{?}$, $\text{b = 125}\text{A}\text{?}$, $\text{c = 54}\text{A}\text{?}$. There is one molecule in the asymmetric unit.     

Crystallizations and preliminary X-ray studies of calotropins DI and DII

Crystals of calotropin DI (M_r 23,400), have been prepared by microdialysis against 5% (w/v) polyethylene glycol 20,000 in water, pH 7.0. They have orthorhombic space group P2₁2₁2₁ with cell parameters $\text{a = 57.5}\text{A}\text{?}\text{, b = 86.2}\text{A}\text{?}\text{, c = 40.3}\text{A}\text{?}$. Crystals of calotropin DII (M_r 24,000), prepared by the same technique against 5% (w/v) polyethylene glycol 20,000 in phosphate buffer of low ionic strength, pH 7.0, display monoclinic space group C2 with cell parameters $\text{a = 135.8}\text{A}\text{?}\text{, b = 32.0}\text{A}\text{?}\text{, c = 47.7}\text{A}\text{?}\text{, β = 103.80 °}$. In both cases, there is only one molecule in the asymmetric unit.     

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.     

Structural study of crystalline auromomycin: Preliminary X-ray diffraction study of auromomycin and macromomycin

Auromomycin and macromomycin from the organism Streptomyces macromomyceticus have been crystallized. The X-ray diffraction pattern of crystals of each molecule is consistent with space group P2₁2₁2 with cell parameters $\text{a = 46.45}\text{A}\text{?}\text{, b = 54.34}\text{A}\text{?}\text{and}\text{c = 42.03}\text{A}\text{?}$ for auromomycin, and $\text{a = 46.45}\text{A}\text{?}\text{, b = 54.52}\text{A}\text{?}\text{and}\text{c = 41.54}\text{A}\text{?}$ for macromomycin. Diffraction analysis of auromomycin is in progress.     

Letter: Crystallographic study of an esteroproteolytic enzyme

The esteroproteolytic enzyme, a serine protease from porcine pancreas, has been crystallized and characterized by X-ray diffraction. Two closely related crystal forms were observed. The unit cell dimensions of the first form are $\text{a = 59.2}\text{A}\text{?}\text{, b = 96.4}\text{A}\text{?}\text{and}\text{c = 47.4}\text{A}\text{?}$, space group P2₁2₁2 with one molecule (mol. wt 30,000) per asymmetric unit. The unit cell dimensions of the second form are $\text{a = 59.2}\text{A}\text{?}\text{, b = 96.4}\text{A}\text{?}\text{and}\text{c = 94.8}\text{A}\text{?}$, space group P2₁2₁2₁. Mercury derivatives of enzyme inhibitors were used to obtain multiple isomorphous heavy-atom substituents suitable for phase determination.     

Preliminary crystallographic data for lysozyme produced by Streptomyces erythraeus.

Crystals of lysozyme from Streptomyces erythraeus are orthorhombic, space group P2₁2₁2₁ with unit cell dimensions: $\text{a = 50.01}\text{A}\text{?}\text{, b = 61.98}\text{A}\text{?}$ and $\text{c = 67.85}\text{A}\text{?}$; and one molecule, of molecular weight about 18,500, per asymmetric unit.     

Crystallization and preliminary crystallographic data for cytochrome c551.5 (c7) from Desulfuromonas acetoxidans.

Cytochrome c₇, a low potential, three heme-containing protein (molecular weight 9800) was isolated from Desulfuromonas acetoxidans and crystallized from polyethylene glycol solutions. The crystals belong to the orthorhombic space group P2₁2₁2₁, with unit-cell dimensions $\text{a = 44·10}\text{A}\text{?}\text{, b = 37·55}\text{A}\text{?}$ and $\text{c = 45·08}\text{A}\text{?}$ and have one molecule of protein per asymmetric unit.     

Crystallography of alpha-lactalbumin. III. Crystals of baboon milk alpha-lactalbumin.

Crystals of baboon α-lactalbumin suitable for structure analysis at high resolution have been obtained. They have cell dimensions $\text{a = 35.5}\text{A}\text{?}\text{, b = 69.1}\text{A}\text{?}\text{, c = 46.1}\text{A}\text{?}$, space group P2₁2₁2 and contain one molecule of α-lactalbumin per asymmetric unit.     

Preliminary x-ray study of crystals of mitogenic lectin from pea seeds.

Crystals of mitogenic lectin from pea seeds (Pisum sativum) have been grown. The crystals are in space group P2₁2₁2₁ with unit cell dimensions: $\text{a = 51.0 ± 0.2}\text{A}\text{?}\text{, b = 617 ± 0.2}\text{A}\text{?}\text{, c = 137.6 ± 0.5}\text{A}\text{?}$. The asymmetric unit has one protein molecule.     

Crystallographic study of plastocyanins

Crystals of plastocyanins from pea and corn leaves have been obtained. Both are suitable for X-ray structure analysis with a resolution up to 1.8 Å. The crystal form of plastocyanin from pea leaves belongs to the space group P2₁2₁2₁ with unit cell dimensions: $\text{a = 49.0}\text{A}\text{?}\text{, b = 53.3}\text{A}\text{?}\text{, c = 82.6}\text{A}\text{?}$. The assumed number of protein molecules per asymmetric unit of the unit cell is two. Crystals of the oxidized (Cu²⁺) and reduced (Cu⁺) forms are isomorphic. No essential differences in spot intensities for the main zone with a resolution of 3 Å were revealed. The crystal form of plastocyanin from corn leaves belongs to the space group P1 with unit cell parameters: $\text{a = 24.8}\text{A}\text{?}\text{, b = 30.0}\text{A}\text{?}\text{, c = 58.5}\text{A}\text{?}$ and α = 96° 10′, β = 87°08′, γ = 78°40′. The assumed number of protein molecules per asymmetric unit is two.     

Crystallographic data for lysozyme from the egg white of the Embden goose

Two crystal forms of lysozyme from the egg white of the embden goose (Anser anser) have been obtained, both of which are suitable for X-ray diffraction analysis. The monoclinic form has space group P2₁ with cell dimensions $\text{a = 38.3}\text{A}\text{?}\text{, b = 65.7}\text{A}\text{?}\text{, c = 45.2}\text{a}\text{?}$, β = 116 ° and the triclinic form (space group P1) has cell dimensions of $\text{a = 39.9}\text{A}\text{?}\text{, b = 42.2}\text{A}\text{?}\text{, c = 57.9}\text{A}\text{?}$ and α = 98.8 °, β = 102.5 °, γ = 90.5 °.     

X-ray analysis of a progesterone-binding protein (uteroglobin): preliminary results

Uteroglobin, which is a progesterone-binding protein of the rabbit uterine secretion, has been crystallized and subjected to X-ray diffraction analysis. Two crystalline forms have been observed: a triclinic one ($\text{P1, Z = 2, a = 36.36 (4)}\text{A}\text{?}\text{, b = 37.40 (4)}\text{A}\text{?}\text{, c = 53.28 (4)}\text{A}\text{?}\text{, α = 104.6 (1) °, β = 97.0 (1) °, γ = 111.3(1) °}$); and an orthorhombic one for which the cell is C-centred with $\text{a = 50.86 (5)}\text{A}\text{?}\text{, b = 52.22 (5)}\text{A}\text{?}\text{, c = 47.28 (5)}\text{A}\text{?}$, space group C222₁, Z = 4. Three isomorphous derivatives have been obtained. The crystals appear suitable for detailed study of the three-dimensional structure of the protein.     

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 cow α-lactalbumin

Three new crystal forms of cow α-lactalbumin are described. A trigonal form in space group P3₁21 or P3₂21 has unit cell dimensions: $\text{a = b = 57.4}\text{A}\text{?}\text{, c = 75.0}\text{A}\text{?}$. A hexagonal form in space group P622 has unit cell dimensions: $\text{a = b = 94.0}\text{A}\text{?}\text{, c = 67.1}\text{A}\text{?}$. A second trigonal form grown in the presence of calcium ions belongs to space group P321 with unit cell dimensions: $\text{a = b = 93.7}\text{A}\text{?}\text{, c = 66.9}\text{A}\text{?}$. The significance of these new crystal forms to the structure determination of cow α-laetalbumin is discussed.     

A preliminary crystallographic study of wheat germ agglutinin

Wheat germ agglutinin crystallizes in two monoclinic space groups, P2₁ and C2, under identical crystallization conditions. Unit cell dimensions are $\text{a = 73.8}\text{A}\text{?}\text{, b = 51.2}\text{A}\text{?}\text{, c = 90.8}\text{A}\text{?}\text{, γ = 90 °}$ for $\text{P2}{}_1\text{; a = 51.31}\text{A}\text{?}\text{, b = 73.35}\text{A}\text{?}\text{, c = 91.45}\text{A}\text{?}\text{, β = 97.75 °}$ for C2, both with eight subunit molecules in the unit cell. The C2 crystals were chosen as suitable for investigating the three-dimensional structure to high resolution, because of their smaller asymmetric unit (containing the dimer), and also because they display better diffraction patterns.