# Mechanism of initiation of lipid binding of apolipoprotein A-I

> **NIH NIH SC3** · CALIFORNIA STATE UNIVERSITY LONG BEACH · 2021 · $110,625

## Abstract

Project Summary
Apolipoprotein (apo) A-I is a multifunctional protein with a well-established role in reverse
cholesterol transport and is an important player in heart disease. It is the main protein
component of high-density lipoprotein (HDL), which circulates through plasma promoting
cholesterol efflux. While a high-resolution structure is not known yet, extensive biophysical
analysis has suggested that the 28 kDa protein is made of two domains, each of which contain
amphipathic α-helices for association with lipid surfaces. The C-terminal (CT) domain contains
helical segments that initiate lipid binding, and is also the site responsible for self-association. It
is a critical part of the protein needed for maturation of lipid-free apoA-I into HDL. Conflicting
data exist about the role of the N-terminal (NT) helices in this process, as well as the precise
helical segments of the CT domain. We have recently discovered that CT lysine residues are
critical for self-association, and were able to create a monomeric version of the protein. To
identify apoA-I helical segments important for initiation of lipid binding and self-association,
which are closely connected, we developed a chimeric protein. This chimera will be used to
identify which helical segments of apoA-I, both NT and CT α-helices, are required for initiation of
lipid binding and self-association. To identify the specific amino acid residues of the CT domain
required in self-association, site-directed mutagenesis will be employed. All proteins will be
expressed in a bacterial expression system, purified by affinity and size-exclusion
chromatography, and characterized for structure and function. The results of this study will lead
to a much better understanding in the domain organization of this critical apolipoprotein, their
structure function relationship, and may also provide opportunities for high-resolution structural
analysis using monomeric apoA-I.

## Key facts

- **NIH application ID:** 10189632
- **Project number:** 5SC3GM089564-11
- **Recipient organization:** CALIFORNIA STATE UNIVERSITY LONG BEACH
- **Principal Investigator:** PAUL Michiel WEERS
- **Activity code:** SC3 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $110,625
- **Award type:** 5
- **Project period:** 2010-01-01 → 2023-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10189632

## Citation

> US National Institutes of Health, RePORTER application 10189632, Mechanism of initiation of lipid binding of apolipoprotein A-I (5SC3GM089564-11). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10189632. Licensed CC0.

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