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Titolo:
Contrast analysis of the composition of ribosomes extracted with differentpurification procedures
Autore:
Briganti, G; Giordano, R; Londei, P; Valle, F;
Indirizzi:
Univ Rome La Sapienza, Dept Phys, INFM, I-00185 Rome, Italy Univ Rome La Sapienza Rome Italy I-00185 Phys, INFM, I-00185 Rome, Italy Dept Phys Messina, INFM, I-98166 Messina, Italy Dept Phys Messina Messina Italy I-98166 na, INFM, I-98166 Messina, Italy Univ Bari, Inst Gen Biol, Bari, Italy Univ Bari Bari ItalyUniv Bari, Inst Gen Biol, Bari, Italy Univ La Sapienza, Policlin Umberto I, Dept Cellular Biotechnol & Hematol, I-00185 Rome, Italy Univ La Sapienza Rome Italy I-00185 chnol & Hematol, I-00185 Rome, Italy Univ Lausanne, BSP, Inst Condensed Matter Phys, CH-1015 Lausanne, Switzerland Univ Lausanne Lausanne Switzerland CH-1015 CH-1015 Lausanne, Switzerland
Titolo Testata:
JOURNAL OF APPLIED CRYSTALLOGRAPHY
, volume: 33, anno: 2000,
parte:, 4
pagine: 1113 - 1118
SICI:
0021-8898(20000801)33:<1113:CAOTCO>2.0.ZU;2-#
Fonte:
ISI
Lingua:
ENG
Soggetto:
ESCHERICHIA-COLI; NEUTRON-SCATTERING; PROTEIN; RNA;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
14
Recensione:
Indirizzi per estratti:
Indirizzo: Briganti, G Univ Rome La Sapienza, Dept Phys, INFM, PA Moro 2, I-00185 Rome, Italy Univ Rome La Sapienza PA Moro 2 Rome Italy I-00185 ome, Italy
Citazione:
G. Briganti et al., "Contrast analysis of the composition of ribosomes extracted with differentpurification procedures", J APPL CRYS, 33, 2000, pp. 1113-1118

Abstract

The composition and hydration of E. coli ribosomes isolated with differentpurification protocols has been analysed by combining two experimental techniques: measurements of small-angle neutron scattering (SANS), for two different isotopic solvent compositions, and refractive index (RI) increments. From the contrast between the solvent and solute scattering densities and the molar polarizability, determined experimentally with SANS and RI measurements, three independent equations are obtained and three unknown quantities are determined: (i) the volume of the solute hydrated skeleton Vs, (ii) the material contained in it, namely the biological components, intrinsic (rRNA and proteins) and extrinsic, such as aminoacylsynthetase and elongation factors, (iii) the number of water molecules structurally bound to the ribosome and nonexchangeable with the solvent. From the form factor at infinite contrast, a second definition of the solute volume is obtained, V-s(c), which represents the volume within the contour surface of the ribosome. This value is generally larger than Vs and can include a certain amount of water molecules, i.e. those inside the volume (V-s(c)-V-s). Considering the molar volume of this water to be equal to that of the bulk water, it is possible to evaluate its amount. The particle density calculated from the ribosome components in V-s(c), including proteins, RNA, bound and unbound water molecules, corresponds to the buoyant density measured for E. coli 70S particles. The two ribosomal preparations display different performances in protein synthesis; hence the results indicate that the optimal condition corresponds to a wider skeleton and contour volume but containing a smaller amount of segregated water molecules. It is believed that the method provides a reliable technique to determine the composition of ribosomes under various experimental conditions.

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Documento generato il 30/09/20 alle ore 09:44:08