skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Solution Structure of an Intramembrane Aspartyl Protease via Small Angle Neutron Scattering

Abstract

Intramembrane aspartyl proteases (IAPs) comprise one of four families of integral membrane proteases that hydrolyze substrates within the hydrophobic lipid bilayer. IAPs include signal peptide peptidase, which processes remnant signal peptides from nascent polypeptides in the endoplasmic reticulum, and presenilin, the catalytic component of the γ-secretase complex that processes Notch and amyloid precursor protein. Despite their broad biomedical reach, basic structure-function relationships of IAPs remain active areas of research. Characterization of membrane-bound proteins is notoriously challenging due to their inherently hydrophobic character. For IAPs, oligomerization state in solution is one outstanding question, with previous proposals for monomer, dimer, tetramer, and octamer. Here we used small angle neutron scattering (SANS) to characterize n-dodecyl-β-D-maltopyranoside (DDM) detergent solutions containing and absent a microbial IAP ortholog. A unique feature of SANS is the ability to modulate the solvent composition to mask all but the enzyme of interest. The signal from the IAP was enhanced by deuteration and, uniquely, scattering from DDM and buffers were matched by the use of both tail-deuterated DDM and D 2O. The radius of gyration calculated for IAP and the corresponding ab initio consensus model are consistent with a monomer. The model is slightly smaller than the crystallographic IAP monomer,more » suggesting a more compact protein in solution compared with the crystal lattice. In conclusion, our study provides direct insight into the oligomeric state of purified IAP in surfactant solution, and demonstrates the utility of fully contrast-matching the detergent in SANS to characterize other intramembrane proteases and their membrane-bound substrates.« less

Authors:
 [1]; ORCiD logo [2]; ORCiD logo [2]; ORCiD logo [2];  [1]
  1. Georgia Inst. of Technology, Atlanta, GA (United States). School of Chemistry and Biochemistry
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Neutron Scattering Division
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23); National Science Foundation (NSF)
OSTI Identifier:
1422538
Grant/Contract Number:
AC05-00OR22725; DMR-0520547; 0845445
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Biophysical Journal
Additional Journal Information:
Journal Volume: 114; Journal Issue: 3; Journal ID: ISSN 0006-3495
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; neutron scattering; membrane protein; detergent; intramembrane proteolysis

Citation Formats

Naing, Swe-Htet, Oliver, Ryan C., Weiss, Kevin L., Urban, Volker S., and Lieberman, Raquel L. Solution Structure of an Intramembrane Aspartyl Protease via Small Angle Neutron Scattering. United States: N. p., 2018. Web. doi:10.1016/j.bpj.2017.12.017.
Naing, Swe-Htet, Oliver, Ryan C., Weiss, Kevin L., Urban, Volker S., & Lieberman, Raquel L. Solution Structure of an Intramembrane Aspartyl Protease via Small Angle Neutron Scattering. United States. doi:10.1016/j.bpj.2017.12.017.
Naing, Swe-Htet, Oliver, Ryan C., Weiss, Kevin L., Urban, Volker S., and Lieberman, Raquel L. Tue . "Solution Structure of an Intramembrane Aspartyl Protease via Small Angle Neutron Scattering". United States. doi:10.1016/j.bpj.2017.12.017.
@article{osti_1422538,
title = {Solution Structure of an Intramembrane Aspartyl Protease via Small Angle Neutron Scattering},
author = {Naing, Swe-Htet and Oliver, Ryan C. and Weiss, Kevin L. and Urban, Volker S. and Lieberman, Raquel L.},
abstractNote = {Intramembrane aspartyl proteases (IAPs) comprise one of four families of integral membrane proteases that hydrolyze substrates within the hydrophobic lipid bilayer. IAPs include signal peptide peptidase, which processes remnant signal peptides from nascent polypeptides in the endoplasmic reticulum, and presenilin, the catalytic component of the γ-secretase complex that processes Notch and amyloid precursor protein. Despite their broad biomedical reach, basic structure-function relationships of IAPs remain active areas of research. Characterization of membrane-bound proteins is notoriously challenging due to their inherently hydrophobic character. For IAPs, oligomerization state in solution is one outstanding question, with previous proposals for monomer, dimer, tetramer, and octamer. Here we used small angle neutron scattering (SANS) to characterize n-dodecyl-β-D-maltopyranoside (DDM) detergent solutions containing and absent a microbial IAP ortholog. A unique feature of SANS is the ability to modulate the solvent composition to mask all but the enzyme of interest. The signal from the IAP was enhanced by deuteration and, uniquely, scattering from DDM and buffers were matched by the use of both tail-deuterated DDM and D2O. The radius of gyration calculated for IAP and the corresponding ab initio consensus model are consistent with a monomer. The model is slightly smaller than the crystallographic IAP monomer, suggesting a more compact protein in solution compared with the crystal lattice. In conclusion, our study provides direct insight into the oligomeric state of purified IAP in surfactant solution, and demonstrates the utility of fully contrast-matching the detergent in SANS to characterize other intramembrane proteases and their membrane-bound substrates.},
doi = {10.1016/j.bpj.2017.12.017},
journal = {Biophysical Journal},
number = 3,
volume = 114,
place = {United States},
year = {Tue Feb 06 00:00:00 EST 2018},
month = {Tue Feb 06 00:00:00 EST 2018}
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on February 6, 2019
Publisher's Version of Record

Save / Share: