# Ribosome Structure and Function

> **NIH NIH R35** · UNIVERSITY OF CALIFORNIA SANTA CRUZ · 2023 · $765,988

## Abstract

Project Summary
 This project focuses on understanding the molecular mechanisms underlying the
coupled translocation of mRNA and tRNAs during protein synthesis. It includes the important
related problems of how the translational reading frame is preserved (or shifted) and how the
ribosomal helicase unwinds structured mRNAs. Our laboratory uniquely uses a combination of
biochemistry, structural biology, genetics, FRET and computational methods to address these
challenging problems. We are also extending our approaches to include single-molecule optical
tweezer methods, in collaboration with the Bustamante laboratory (UC Berkeley) and single-
molecule FRET, in collaboration with the Ermolenko laboratory (Univ. of Rochester), as well as
cryo-electron microscopy, in collaboration with the Chiu laboratory (Stanford/SLAC).
 In previous studies, we have determined the structures of trapped translocation
intermediates, which have provided unexpected insights into how the movements of mRNA and
tRNA through the ribosome are coupled to large- and small-scale conformational changes in the
structure of the ribosome itself. We then created FRET pairs that allowed us to correlate
intersubunit rotation, movement of the L1 stalk and rotation of the 30S subunit head domain with
movements of mRNA and tRNA. We plan to extend this search to discover new intermediate
states. Having exhausted previous strategies for trapping translocation intermediates, we will
use a new approach which exploits a set of dominant-lethal mutations in all five structural
domains of elongation factor EF-G that we expect will block translocation at different steps.
 Development of a novel fluorescent labeling approach that will allow site-specific labeling
of FRET pairs directly to ribosomal RNA will overcome technical barriers to single-molecule
studies of ribosome dynamics, including studies using simultaneous measurement of molecular
forces and FRET changes in the ribosome, in collaboration with the Bustamante group. Finally,
we have designed model structured mRNAs that will provide the basis for studying the
mechanism of the mRNA helicase and for determination of the structures of translocation
complexes stalled in the act of encountering and unwinding an mRNA helix.

## Key facts

- **NIH application ID:** 10597704
- **Project number:** 5R35GM118156-08
- **Recipient organization:** UNIVERSITY OF CALIFORNIA SANTA CRUZ
- **Principal Investigator:** HARRY F NOLLER
- **Activity code:** R35 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2023
- **Award amount:** $765,988
- **Award type:** 5
- **Project period:** 2016-04-01 → 2026-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10597704

## Citation

> US National Institutes of Health, RePORTER application 10597704, Ribosome Structure and Function (5R35GM118156-08). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10597704. Licensed CC0.

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