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.     

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.     

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.     

Purification and preliminary crystallographic studies on azurin and cytochrome c' from Alcaligenes denitrificans and Alcaligenes sp. NCIB 11015.

Purification and crystallisation procedures are reported for azurin and cytochrome c′ from Alcaligenes denitrificans and Alcaligenes sp. NCIB 11015. The azurin crystals from A. denitrificans are suitable for high-resolution X-ray structure analysis. They are orthorhombic, space group C222₁ (with marked tetragonal pseudo-symmetry), cell dimensions $\text{a = 75.0}\text{A}\text{?}\text{, b = 74.1}\text{A}\text{?}\text{, c = 99.5}\text{A}\text{?}$, with two molecules per asymmetric unit. The cytochrome c′ crystals from both species are hexagonal, space group P6₁22 (or P6₅22), cell dimensions $\text{a = b = 54.7}\text{A}\text{?}\text{, c ~ 185}\text{A}\text{?}$, γ = 120 °, with one subunit (molecular weight 14,000) in the asymmetric unit.     

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.     

Crystals of myohemerythrin

Crystals have been grown of metazide myohemerythrin from the sipunculid Dendrostomum pyroides. The crystals are in space group P2₁2₁2₁ and have unit cell dimensions of $\text{a = 41.6}\text{A}\text{?}\text{, b = 80.0}\text{A}\text{?}\text{and}\text{c = 37.8}\text{A}\text{?}$. An asymmetric unit contains a single myohemerythrin molecule.     

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 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.     

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.     

Crystallographic studies of immunoglobulins: crystallization of the Fc fragment of rabbit IgG with and without cleavage of the inter-chain disulphide bridge

The Fc fragment was prepared from rabbit immunoglobulin G by digestion with papain, both with the inter-chain disulphide bond intact, and after reduction and alkylation. These two types of Fc crystallized in different, yet related forms, each with one dimer in the asymmetric unit. The covalently linked dimer crystallized in space group $\text{P2}{}_1\text{; a = 68.85 ± 0.05}\text{A}\text{?}\text{, b = 72.50 ± 0.05}\text{A}\text{?}\text{, c = 60.40 ± 0.05}\text{A}\text{?}$ and β = 105.1 ± 0.2 °. The reduced, non-covalently linked dimer also crystallized in space group $\text{P2}{}_1\text{; a = 81.55 ± 0.05}\text{A}\text{?}\text{, b = 55.65 ± 0.05}\text{A}\text{?}\text{, c = 68.85 ± 0.05}\text{A}\text{?}$ and β = 1051 ± 0.2 °. A non-crystallographic 2-fold axis relating the two identical polypeptide chains is clearly visible in the h0l projection of the second crystal form.     

A salt-induced conformational change in crystals of the synthetic DNA tetramer d(CpGpCpG)

From a low-salt solution, d(CpGpCpG) crystallizes in space group P6₁22 with $\text{a = b = 30.8}\text{A}\text{?}\text{and}\text{c = 43.6}\text{A}\text{?}$. From a high-salt solution, d(CpGpCpG) crystallizes in space group $\text{C222}{}_1\text{with}\text{a = 19.5}\text{A}\text{?}$, $\text{b = 31.3}\text{A}\text{?}$, and $\text{c = 64.7}\text{A}\text{?}$. The transition between these two forms appears to be fully reversible in the crystalline state. Native data sets have been collected and Patterson maps calculated from both low and high-salt crystals in preparation for structure analysis.     

Crystallographic study of the large tryptic fragments of elongation factor G from Escherichia coli

Crystals of N- and C-terminal fragments of elongation factor G (EF-G) from Escherichia coli have been grown from the preparations obtained by limited tryptic hydrolysis. Molecular masses of these fragments are equal to about 49,000 and 25,000, respectively. In the form of an additive complex they appear to be a major part of the native spatial structure of EF-G (Alakhov et al., 1979). Crystals of N-terminal fragment belong to space group P4₁2₁2 or P4₃2₁2 with unit cell dimensions $\text{a = b = 76.6}\text{A}\text{?}\text{and}\text{c = 191.6}\text{A}\text{?}$. Crystals of C-terminal fragment belong to space group P4₁22 or P4₃22 with unit cell dimensions $\text{a = b = 77.1}\text{A}\text{?}\text{and}\text{c = 75.0}\text{A}\text{?}$. In both cases the assumed number of protein molecules per asymmetric part of the unit cell is one.     

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 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.     

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.     

Crystallisation of tRNALeuCUG from Escherichia coli after purification with hydroxyapatite.

tRNA_CUG^Leu from E. Coli was purified by column chromatography on benzoylated DEAE-cellulose, followed by hydroxyapatite prepared by an improved method. Crystals obtained by vapour diffusion gave X-ray diffraction out to 7 Å in the hk0 projection and 10 Å in h0?. The space group was P4₂2₁2 with $\text{a = b = 133}\text{A}\text{?}$, $\text{c = 66}\text{A}\text{?}$ and 8 molecules in the unit cell. Birefringence showed preferred orientation of RNA helical regions in the ab plane.     

Crystallographic data of the selenoenzyme glutathione peroxidase

Glutathione peroxidase prepared from bovine erythrocytes yields small, but well-ordered plate-like crystals. X-ray investigation shows them to belong to monoclinic space group C2. Unit cell dimensions are: $\text{a = 90.4}\text{A}\text{?}\text{, b = 109.5}\text{A}\text{?}\text{, c = 58.6}\text{A}\text{?}$, β = 99 ° ± 15 min. The crystal density is ?_c = 1.36 ± 0.02 g.cm^?3. Consequently, the asymmetric unit of the crystal cell is occupied by one tetrameric molecule of M_r 84,000. Matthew's (1968) parameter Γ_M is calculated to be 1.71 ų/dalton.     

Preliminary X-ray data for the ribose binding protein from Salmonella typhimurium

Crystals of the periplasmic ribose binding protein of Salmonella typhimurium have been subjected to X-ray analysis. The crystals grow as rectangular parallelopipeds with the symmetry of space group P2₁. Unit cell dimensions are $\text{a = 64·4}\text{A}\text{?}\text{, b = 60·6}\text{A}\text{?}\text{, c = 62·8}\text{A}\text{?}$, and β = 91·25 °. There are two molecules of molecular weight 29,000 per asymmetric unit.     

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.     

Crystal data, molecular dimensions and molecular symmetry in cytochrome oxidase from Pseudomonas aeruginosa.

Pseudomonas aeruginosa cytochrome oxidase (nitrite reductase, cytochrome cd) has been crystallized in space group P2₁2₁2 with cell dimensions $\text{a = 122.8}\text{A}\text{?}\text{, b = 87.2}\text{A}\text{?}\text{, c = 73.4}\text{A}\text{?}$. Density measurements suggest that the asymmetric unit contains one 63,000 molecular weight subunit of the dimeric molecule. Crystal data agree well with electron microscopy of single molecules. The X-ray pattern extends beyond 2.5 Å resolution, and structure analysis is in progress.