Structure and dynamics of a detergent-solubilized membrane protein: measurement of amide hydrogen exchange rates in M13 coat protein by /sub 1/H NMR spectroscopy

Journal Article · Tue Apr 19 00:00:00 EDT 1988 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00408a015· OSTI ID:6999675

O'Neil, J D.J.; Sykes, B D

The coat protein of bacteriophage M13 is inserted into the inner membrane of Escherichia coli where it exists as an integral membrane protein during the reproductive cycle of the phage. The protein sequence consists of a highly hydrophobic 19-residue central segment flanked by an acidic 20-residue N-terminus and a basic 11-residue C-terminus. The authors have measured backbone amide hydrogen exchange of the protein solubilized in perdeuteriated sodium dodecyl sulfate using /sup 1/H nuclear magnetic resonance (NMR) spectroscopy. Direct proton exchange-out measurements in D/sub 2/O at 24 /sup 0/C were used to follow the exchange of the slowest amides in the protein. Multiple exponential fitting of the exchange data showed that these amides exchanged in two kinetic sets with exchange rates that differed by more than 100-fold. Steady-state saturation-transfer techniques were also used to measure exchange. These methods showed that 15-20 amides in the protein are very stable at 55/sup 0/C and that bout 30 amides have exchange rates retarded by at least 10/sup 5/-fold at 24/sup 0/C. Saturation-transfer studies also showed that the pH dependence of exchange in the hydrophilic termini was unusual. Relaxation and solid-state NMR experiments have previously shown that the majority of the protein backbone is rigid on the picosecond to microsecond time scale, except for the extreme ends of the molecule which are mobile. The hydrogen exchange results, which are sensitive to a much longer time scale, suggest a stable core with a progressive increase in amplitude or frequency of motions as the ends of the protein are approached.

• Research Organization: Univ. of Alberta, Edmonton (Canada)
• OSTI ID: 6999675
• Journal Information: Biochemistry; (United States), Vol. 27:8
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
PROTEINS
HYDROGEN TRANSFER
NUCLEAR MAGNETIC RESONANCE
AMIDES
CELL MEMBRANES
DETERGENTS
ESCHERICHIA COLI
HEAVY WATER
PROTONS
ADDITIVES
BACTERIA
BARYONS
CELL CONSTITUENTS
ELEMENTARY PARTICLES
EMULSIFIERS
FERMIONS
HADRONS
HYDROGEN COMPOUNDS
MAGNETIC RESONANCE
MEMBRANES
MICROORGANISMS
NUCLEONS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXYGEN COMPOUNDS
RESONANCE
SURFACTANTS
WATER
WETTING AGENTS
550601* - Medicine- Unsealed Radionuclides in Diagnostics