# Mechanisms and Applications of CRISPR-Cas Enzymes

> **NIH NIH R01** · FLORIDA STATE UNIVERSITY · 2022 · $379,446

## Abstract

Description: The discovery that bacteria and archaea employ an RNA-guided immunity mechanism to
defend themselves from invasive genetic elements offers an unprecedented opportunity for
understanding fundamental microbial biology and for developing biotechnology tools. Clustered, regularly
interspaced, short palindromic repeats (CRISPR) loci encode two major classes of mechanistically
different RNA-guided enzymes that can degrade invasive nucleic acids while avoiding self-nucleic acids
or elicit secondary immunity through synthesis of second messengers. Understanding the molecular
mechanisms of these distinct classes of enzymes has important implications in basic
enzymology, antibiotics resistance epidemics, human microbiome research, virus and cancer
detection and genome editing. The Li laboratory has identified and established the conditions for
studying phenotypical members of the two classes of CRISPR-Cas enzymes and is poised to unveil novel
molecular mechanisms as well as to develop useful tools. Both classes share the trade of being RNA-
guided and invader-specific. However, they differ drastically in enzyme composition and biochemical
mechanisms and, therefore, require a broad range of investigative tools and expertise. An integrated
approach ranging from cell-based assays, to structural biology and to fundamental enzymology will be
employed to compare and contrast the mode of interference by the Class 1 and 2 enzymes, leading to
an understanding of how microbe impact human health and biosphere and to an ultimate goal of
developing CRISPR-based technology. The Li laboratory has assembled a team of scientists with
complementary expertise in microbiology, nucleic acid biochemistry, mammalian cell biology, virus
detection, X-ray crystallography, and high-throughput cryogenic electron microscopy, in order to
maximize the impact while mitigating risks of the research.
Relevance: The CRISPR elements are found in more than 40% bacteria and are critical to maintenance
of the overall microbial environment. The frequent occurrence of CRISPR in medically important bacteria
that include but not limited to Yersinia pestis, Mycobacterium tuberculosis, Haemophilus influenzae,
Helicobacter pylori, Neisseria meningitides, Vibrio vulnificus, Staphylococcus aureus, Salmonella Typhi,
Clostridium tetani, and human microbiome relates CRISPR directly to human health. A thorough
understanding of the CRISPR immunity has important implications in eradicating virulence and creating
new antimicrobial strategies. While one of the CRISPR enzymes, namely Cas9, has been repurposed to
serve as a user-specified genome-editing tool with ever-increasing utility, we are yet to unleash the full
potential of the CRISPR-derived tools in biomedical applications. The proposed research is aimed at
overcoming current limitations while expanding the capability.

## Key facts

- **NIH application ID:** 10446170
- **Project number:** 2R01GM099604-09A1
- **Recipient organization:** FLORIDA STATE UNIVERSITY
- **Principal Investigator:** Hong Li
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $379,446
- **Award type:** 2
- **Project period:** 2012-05-01 → 2026-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10446170

## Citation

> US National Institutes of Health, RePORTER application 10446170, Mechanisms and Applications of CRISPR-Cas Enzymes (2R01GM099604-09A1). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10446170. Licensed CC0.

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