Changes in Rhodospirillum rubrum cytochrome c/sub 2/ and subsequent renaturation: An /sup 15/N NMR study

Journal Article · Sun May 01 04:00:00 EDT 1988 · Proc. Natl. Acad. Sci. U.S.A.; (United States)

DOI:https://doi.org/10.1073/pnas.85.9.2894· OSTI ID:6401008

Yu, L P; Smith, G M

The /sup 15/N-enriched ferrocytochrome c/sub 2/from Rhodospirillum rubrum was studied by /sup 15/N NMR at different solvent pH values. The mobility and chemical shift to the N-terminal glutamic acid (335.4 ppm at pH 5.1) were found to depend on pH. It was least mobile between pH 8 and 9.0, which is explained in terms of pH-dependent conformational changes and formation of salt linkages and/or hydrogen bonds. The resonances of the lysine side chains are centered around 341.7 ppm at low pH and move upfield with pH by about 8.4 ppm with pH/sub a/ values of 10.8. The exchange rates of the epsilonNH protons are lowest near the pK/sub a/ values. The protein is very stable in the pH range between 4.9 and 10.0 but unfolds abruptly at pH 10.5-11. Denaturation was verified by the measurement of several parameters by NMR. The renaturation of the protein demonstrates that the folding begins with reformation of home coordination and establishment of a hydrophobic core, followed by positioning of side chains and peptide backbones linking the nucleation centers. The repositioning processes had time scales of minutes to hours in contrast to the reported values of seconds in some studies.

• Research Organization: Univ. of California, Davis (USA)
• DOE Contract Number: AC02-76CH00016
• OSTI ID: 6401008
• Journal Information: Proc. Natl. Acad. Sci. U.S.A.; (United States), Journal Name: Proc. Natl. Acad. Sci. U.S.A.; (United States) Vol. 85:9; ISSN PNASA
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
BACTERIA
CONFORMATIONAL CHANGES
CYTOCHROMES
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
MICROORGANISMS
NITROGEN 15
NITROGEN ISOTOPES
NMR SPECTRA
NUCLEAR MAGNETIC RESONANCE
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PH VALUE
PIGMENTS
PROTEIN DENATURATION
PROTEINS
RESONANCE
RHODOSPIRILLUM
SPECTRA
STABLE ISOTOPES