Confirmation of the assignment of the low-field proton resonance of serine proteases by using specifically nitrogen-15 labeled enzyme

Journal Article · Sun Dec 01 00:00:00 EST 1985 · Proc. Natl. Acad. Sci. U.S.A.; (United States)

DOI:https://doi.org/10.1073/pnas.82.23.7948· OSTI ID:6194588

Bachovchin, W W

Proton NMR spectra of serine proteases in /sup 1/H/sub 2/O solutions typically show a single resonance at very low magnetic field i.e., 14-18 ppm from dimethylsilylapentanesulfonate. This resonance has been assigned to the proton hydrogen bonded between aspartic acid-102 and histidine-57 (chymotrypsin numbering system) of the charge-relay system or catalytic triad of serine proteases. There have been a number of reports that have cast doubt on its correctness. In the present work the authors have tested this assignment using ..cap alpha..-lytic protease, a bacterial serine protease homologous to elastase, which is specifically labeled with nitrogen-15 at N/sup delta/sub 1// of its single histidine residue. The low-field region of the proton spectra of this labeled enzyme shows a single resonance having the properties reported which, in addition, exhibits spin-spin splitting to the nitrogen-15 label. The observation of this /sup 15/N-/sup delta/sub 1//-H coupling makes the assignment of this resonance to the charge-relay proton unequivocal.

• Research Organization: Tuffs Univ. School of Medicine, Boston, MA
• OSTI ID: 6194588
• Journal Information: Proc. Natl. Acad. Sci. U.S.A.; (United States), Vol. 82:23
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
SERINE PROTEINASES
LABELLING
NMR SPECTRA
MAGNETIC FIELDS
NITROGEN 15
PROTONS
BARYONS
ELEMENTARY PARTICLES
ENZYMES
FERMIONS
HADRONS
HYDROLASES
ISOTOPES
LIGHT NUCLEI
NITROGEN ISOTOPES
NUCLEI
NUCLEONS
ODD-EVEN NUCLEI
PEPTIDE HYDROLASES
SPECTRA
STABLE ISOTOPES
550201* - Biochemistry- Tracer Techniques