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Titolo:
THE C-TERMINAL HALF OF THE ANTI-SIGMA FACTOR FLGM CONTAINS A DYNAMIC EQUILIBRIUM SOLUTION STRUCTURE FAVORING HELICAL CONFORMATIONS
Autore:
DAUGHDRILL GW; HANELY LJ; DAHLQUIST FW;
Indirizzi:
UNIV OREGON,INST MOL BIOL EUGENE OR 97403 UNIV OREGON,INST MOL BIOL EUGENE OR 97403
Titolo Testata:
Biochemistry
fascicolo: 4, volume: 37, anno: 1998,
pagine: 1076 - 1082
SICI:
0006-2960(1998)37:4<1076:TCHOTA>2.0.ZU;2-T
Fonte:
ISI
Lingua:
ENG
Soggetto:
HETERONUCLEAR NMR-SPECTROSCOPY; SALMONELLA-TYPHIMURIUM; BACKBONE DYNAMICS; STAPHYLOCOCCAL NUCLEASE; IMPROVED SENSITIVITY; PROTEINS; BINDING; DNA; FRAGMENT; DOMAINS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
34
Recensione:
Indirizzi per estratti:
Citazione:
G.W. Daughdrill et al., "THE C-TERMINAL HALF OF THE ANTI-SIGMA FACTOR FLGM CONTAINS A DYNAMIC EQUILIBRIUM SOLUTION STRUCTURE FAVORING HELICAL CONFORMATIONS", Biochemistry, 37(4), 1998, pp. 1076-1082

Abstract

FlgM is the inhibitor of sigma(28), a transcription factor specific for the expression of bacterial flagella and chemotaxis genes. FlgM is also exported from the cytoplasm to the outside of the cell during theprocess of flagella filament assembly. In the absence of its targets,FlgM is a dynamic, mostly unfolded, molecule [Daughdrill, G. W., et al. (1997) Nat. Struct. Biol, 4(4), 285-291]. The NMR resonance assignments, dynamics, and average secondary structure of this mostly unfolded form of FlgM are reported here. Because of the dynamic behavior of FlgM, tile deviation of C-alpha chemical shifts from the random coil values was used to lest fur the presence of secondary structure [Wishart, D. S., and Sykes, B. D. (1994) Methods Enzymol. 239, 363-392]. This analysis shows two contiguous regions in the C-terminal half of FlgM with helical C-alpha chemical shifts, These two regions, M60-G73 and A83-A90, contained less than 10 medium-range NOEs, and tile N-15 relaxation parameters suggest the helical structure is not rigid. However, the C-alpha chemical shifts of M60-G73: A83-A90, and other residues in the C-terminal half of FlgM shift toward their canonical random coil values with the addition of a chemical denaturant. Along: with the values of the order parameter, S-2, this observation suggests the C-terminal half of FlgM exists in an equilibrium structural slate that is nonrandom. The same analysis of the N-terminal half of FlgM suggests it mure closely resembles a random coil in conditions with and without denaturant. It appears ?he C-terminal half of FlgM lacks sufficient Intramolecular contacts to form stable secondary or tertiary structures. It is known this C-terminal region becomes rigidly held when FlgM binds sigma(28) (Daughdrill et al,, 1997), and it is possible that binding stabilizes the helical structure. The potential evolutionary relationshipbetween the inhibitory interaction of FlgM with sigma(28) and the autoinhibition observed in sigma(70) is discussed.

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Documento generato il 11/07/20 alle ore 08:51:39