Journal article
Allosterically Coupled Multisite Binding of Testosterone to Human Serum Albumin
Endocrinology (Philadelphia), Vol.162(2), pp.1-14
02/01/2021
DOI: 10.1210/endocr/bqaa199
PMCID: PMC7774055
PMID: 33125473
Abstract
Human serum albumin (HSA) acts as a carrier for testosterone, other sex hormones, fatty acids, and drugs. However, the dynamics of testosterone's binding to HSA and the structure of its binding sites remain incompletely understood. Here, we characterize the dynamics of testosterone's binding to HSA and the stoichiometry and structural location of the binding sites using 2-dimensional nuclear magnetic resonance (2D NMR), fluorescence spectroscopy, 4,4'-dianilino-1,1'-binaphthyl-5,5'-disulfonic acid dipotassium salt partitioning, and equilibrium dialysis, complemented by molecular modeling. 2D NMR studies showed that testosterone competitively displaced 18-[13C]-oleic acid from at least 3 known fatty acid binding sites on HSA that also bind many drugs. Binding isotherms of testosterone's binding to HSA generated using fluorescence spectroscopy and equilibrium dialysis were nonlinear and the apparent dissociation constant varied with different concentrations of testosterone and HSA. The binding isotherms neither conformed to a linear binding model with 1:1 stoichiometry nor to 2 independent binding sites; the binding isotherms were most consistent with 2 or more allosterically coupled binding sites. Molecular dynamics studies revealed that testosterone's binding to fatty acid binding site 3 on HSA was associated with conformational changes at site 6, indicating that residues in in these 2 distinct binding sites are allosterically coupled. There are multiple, allosterically coupled binding sites for testosterone on HSA. Testosterone shares these binding sites on HSA with free fatty acids, which could displace testosterone from HSA under various physiological states or disease conditions, affecting its bioavailability.
Details
- Title: Subtitle
- Allosterically Coupled Multisite Binding of Testosterone to Human Serum Albumin
- Creators
- Abhilash Jayaraj - Indian Institute of Technology DelhiHeidi A Schwanz - Boston UniversityDaniel J Spencer - Brigham and Women's HospitalShalender Bhasin - Brigham and Women's HospitalJames A Hamilton - Boston University School of MedicineB Jayaram - Indian Institute of Technology DelhiAnna L Goldman - Brigham and Women's HospitalMeenakshi Krishna - Brigham and Women's HospitalMaya Krishnan - Brigham and Women's HospitalAashay Shah - University of IowaZhendong Jin - University of IowaEileen Krenzel - Boston UniversitySashi N Nair - Brigham and Women's HospitalSid Ramesh - Brigham and Women's HospitalWen Guo - Brigham and Women's HospitalGerhard Wagner - Harvard UniversityHaribabu Arthanari - Harvard UniversityLiming Peng - Brigham and Women's HospitalBrian Lawney - Harvard UniversityRavi Jasuja - Brigham and Women's Hospital
- Resource Type
- Journal article
- Publication Details
- Endocrinology (Philadelphia), Vol.162(2), pp.1-14
- DOI
- 10.1210/endocr/bqaa199
- PMID
- 33125473
- PMCID
- PMC7774055
- ISSN
- 0013-7227
- eISSN
- 1945-7170
- Grant note
- R43 AG045011 / NIA NIH HHS R44 AG045011 / NIA NIH HHS
- Language
- English
- Date published
- 02/01/2021
- Academic Unit
- Pharmaceutical Sciences and Experimental Therapeutics; Medicinal and Natural Products Chemistry
- Record Identifier
- 9984365878802771
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