scholarly journals The circular dichroism of ribosomal ribonucleic acids

1976 ◽  
Vol 155 (2) ◽  
pp. 279-291 ◽  
Author(s):  
R A. Cox ◽  
W Hirst ◽  
E Godwin ◽  
I Kaiser
Keyword(s):  
Escherichia Coli ◽  
Circular Dichroism ◽  
Frame Of Reference ◽  
Partial Hydrolysis ◽  
Ribonucleic Acids ◽  
Helical Content ◽  
Rrna Species ◽  
The Difference ◽  
Hydrolysis Of ◽  
Circular Dichroïsm

1. The c.d. (circular dichroism) of Drosophila melanogaster rRNA (42% G+C) and of G+C-rich fragments (78% G+C) obtained by partial hydrolysis of rabbit L-rRNA (the largest RNA species isolated from the large subribosomal particle) were measured and found to differ substantially. 2. To interpret these spectra a relation between c.d. of bihelical RNA and % G+C was derived, namely delta epsilonfG = AFG2+bfG+c, where deltaepsilonfG is the c.d. of RNA characterized by a mole fraction, fG, of guanine nucleotides and a, b and c are constants. 3. A frame of reference was established by studying the c.d. of a range of rRNA species, including S-rRNA (the RNA species isolated from the smaller subribosomal particle) and L-rRNA of Escherichia coli. 4. It was found for the rRNA species studied that 0.60+/-0.05 of residues appear to form bihelical secondary structure. 5. A higher helical content, 0.66+/-0.05, was found for the G+C-rich fragment of L-rRNA. The difference in the c.d. of rabbit L-rRNA and of D. melanogaster rRNA is attributable to the dependence of c.d. of the bihelical parts on %G+C. 6. The minimum in c.d. at 295 nm increases with increasing %G+C. The c.d. of rRNA was compared with that of the parent subparticle in this region of the spectrum, where high precision may be attained.

scholarly journals Circular dichroism investigation of Escherichia coli adenylate kinase.

1987 ◽  
Vol 262 (6) ◽  
pp. 2502-2506
Author(s):  
M. Monnot ◽  
A.M. Gilles ◽  
I.S. Girons ◽  
S. Michelson ◽  
O. Bârzu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Circular Dichroism ◽  
Adenylate Kinase ◽  
Circular Dichroïsm

Folding Pathway of Escherichia coli Ribonuclease HI: A Circular Dichroism, Fluorescence, and NMR Study

Biochemistry ◽  
1995 ◽  
Vol 34 (51) ◽  
pp. 16552-16562 ◽  
Author(s):  
Kazuhiko Yamasaki ◽  
Kyoko Ogasahara ◽  
Katsuhide Yutani ◽  
Motohisa Oobatake ◽  
Shigenori Kanaya
Keyword(s):  
Escherichia Coli ◽  
Circular Dichroism ◽  
Folding Pathway ◽  
Nmr Study ◽  
Circular Dichroïsm

Magnetic Structure of Multilayers from Soft-X-Ray Magnetic Circular Dichroism

1994 ◽  
Vol 375 ◽  
Author(s):  
C. T. Chen ◽  
Y. U. Idzerda ◽  
C.-C. Kao ◽  
L. H. Tjeng ◽  
H.-J. Lin ◽  
...  
Keyword(s):  
Thin Films ◽  
Circular Dichroism ◽  
Magnetic Circular Dichroism ◽  
Magnetic Thin Films ◽  
X Rays ◽  
X Ray ◽  
Specific Manner ◽  
Left And Right ◽  
The Difference ◽  
Circular Dichroïsm

AbstractSoft-x-ray magnetic circular dichroism (MCD) is the difference between the absorptivity or reflectivity of left and right circularly polarized soft-x-rays at the magnetically interesting L2,3- edges of 3d transition metals or the M4,5-edges of the 4f rare earth elements. Thanks to its large absorption cross-section and strong MCD effect, this technique has become a powerful new means for probing, in an element- and site-specific manner, the magnetic properties of ultra-thin films and multilayers. Soft-x-ray MCD experiments, recently conducted at the Dragon beamline, are utilized to demonstrate the recent progress in this technique and its applications in the research of magnetic thin films.

Physical studies on the ribosomal "A" protein from two archaebacteria, Halobacterium cutirubrum and Methanobacterium thermoautotrophicum

1984 ◽  
Vol 62 (1) ◽  
pp. 44-48 ◽  
Author(s):  
A. T. Gudkov ◽  
S. Yu Venyaminov ◽  
A. T. Matheson
Keyword(s):  
Escherichia Coli ◽  
Circular Dichroism ◽  
Secondary Structure ◽  
Quaternary Structure ◽  
Methanobacterium Thermoautotrophicum ◽  
Sedimentation Equilibrium ◽  
Effect Of Temperature ◽  
Extreme Halophile ◽  
Moderate Halophile ◽  
Circular Dichroïsm

Physical studies on the effect of temperature and ionic conditions on the secondary, tertiary, and quaternary structure of the ribosomal "A" protein, equivalent to L7/L12 in Escherichia coli, from two archaebacteria were performed using circular dichroism and sedimentation equilibrium measurements. The two archaebacteria investigated were Halobacterium cutirubrum, an extreme halophile, and Methanobacterium thermoautotrophicum, a thermophile which also showed properties of a moderate halophile. The changes in the secondary structure and the thermostability of these proteins were directly related to the internal salt concentrations of the two archaebacteria. At the higher salt concentrations the changes in the secondary structure resulted in changes in the tertiary and quaternary structure of these proteins.

Circular dichroism studies of sheep β-lipotropic hormone

1976 ◽  
Vol 54 (11) ◽  
pp. 992-998 ◽  
Author(s):  
Serge St-Pierre ◽  
Claude Gilardeau ◽  
Michel Chrétien
Keyword(s):  
Circular Dichroism ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Conformational Transition ◽  
Acidic Solutions ◽  
Nacl Concentration ◽  
Helical Content ◽  
The Stability ◽  
Far Ultraviolet ◽  
Circular Dichroïsm

The far ultraviolet circular dichroism spectra of sheep β-lipotropic hormone (β-LPH) were recorded under different conditions of pH, temperature, salt concentration, and solvent composition. Results confirm the stability of the hormone in strong basic or acidic solutions; moreover, temperatures up to 50 °C do not seem to affect noticeably the conformation of β-LPH. However, increasing the NaCl concentration or addition of dioxane in the solution brings about a conformational transition of the chain, interpreted as an increase in the helical content. The method of Yang (Chen, Y. H., Yang, J. T. &Martinez, H. M. (1972) Biochemistry 11, 4120–4131) was used to compute the proportion of helical, β, and unordered forms of the hormone chain. The proportions are compared with those obtained from Fasman's predictive method (Chou, P. Y. &Fasman, G. D. (1974) Biochemistry 13, 211–221 and Chou, P. Y. &Fasman, G. D. (1974) Biochemistry 13, 222–245) based on the known amino acid sequence of β-LPH.

Measurement of Magnetic Circular Dichroism Using Alternating Magnetic Fields

1971 ◽  
Vol 25 (2) ◽  
pp. 238-242 ◽  
Author(s):  
A. Abu-Shumays ◽  
G. E. Hooper ◽  
J. J. Duffield
Keyword(s):  
Circular Dichroism ◽  
Light Beam ◽  
Magnetic Circular Dichroism ◽  
Photometric System ◽  
Experimental Apparatus ◽  
State Of Polarization ◽  
The Difference ◽  
Conventional Systems ◽  
Alternating Magnetic Fields ◽  
Circular Dichroïsm

Conventional systems for the measurement of magnetic circular dichroism (MCD) employ a dc magnet in the sample space of a circular dichroism spectropolarimeter, where the state of polarization of the light beam is modulated between left and right circular. The photometric system of the instrument measures the difference between sample absorbances for the two states of polarization of the light beam. The method described in this paper uses a fixed state of polarization of the light beam, left or right circular, an alternating or pulsed magnetic field, and otherwise the same photometric system as the conventional method. The two methods are shown to be mathematically and physically equivalent. The proposed method offers two fundamental advantages: (1) Only the magnetically induced circular dichroism is measured, even in the presence of natural optical activity, and (2) the method is capable of extension to spectral regions where polarization modulation is difficult to achieve. Experimental apparatus using the two methods are described and their relative merits are discussed.

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