# Structural regulation in mitochondrial vitamin-D and vitamin-A metabolizing cytochromes P450

> **NIH NIH R35** · STATE UNIVERSITY OF NEW YORK AT BUFFALO · 2020 · $25,008

## Abstract

ABSTRACT
Cytochrome P450 enzymes (CYPs) are membrane-associated heme proteins that mediate catalysis for a
range of reactions. Seven of the 57 CYP enzymes in humans function in the inner mitochondrial membrane,
where they perform important endogenous reactions in steroid metabolism and vitamin-D activation and
inactivation. A primary focus of our research program is to understand how these CYPs are regulated on a
structural level, particularly for catalytic steps requiring binding of substrate and molecular recognition of
Adrenodoxin (Adx), the soluble ferredoxin required for electron delivery. This is the objective of a recently
activated NIGMS award (R35 GM133375) in which our projects focus on two vitamin-D metabolizing enzymes
(CYP24A1 and CYP27B1) and one vitamin-A metabolizing enzyme (CYP27C1). A central question is how
substrate binding and Adx recognition events are structurally related, via conformational changes in the CYP,
and how such allostery impacts CYP function. However, due to limitations inherent in our biochemical assays
and our current instrumentation, we are not able to accurately quantify molecular interactions between CYP
and ligand and between CYP and Adx. Our laboratory, along with the laboratory of Dr. Mark Sutton, who is
also applying for this supplementation award (R01 GM130761), were recently able to observe an in-lab
demonstration of the OctetRed96e bio-layer interferometry instrument (ForteBio). We have concluded that the
design features of this instrument will allow us to quantify these interactions in a rapid, label-free way. This
capability will allow our program to expand and pose two new questions: i) what are CYP-ligand affinities for
interactions that occur independent of a change in heme spin state? … and ii) How do substrates and inhibitors
alter the specific affinity of the CYP-Adx interaction? Answers to these questions have the potential to expand
our current research program far beyond our current objectives.

## Key facts

- **NIH application ID:** 10135326
- **Project number:** 3R35GM133375-02S1
- **Recipient organization:** STATE UNIVERSITY OF NEW YORK AT BUFFALO
- **Principal Investigator:** David Fernando Estrada
- **Activity code:** R35 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $25,008
- **Award type:** 3
- **Project period:** 2019-09-01 → 2024-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10135326

## Citation

> US National Institutes of Health, RePORTER application 10135326, Structural regulation in mitochondrial vitamin-D and vitamin-A metabolizing cytochromes P450 (3R35GM133375-02S1). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10135326. Licensed CC0.

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