Evidence map›Paper›PMID 40620219›Full record

ArticleBiophysical journal2025

A novel "bio-tag" for cryo-EM studies based on the small, electron-dense protein Csp1.

Weekie Yao, Adam C Oken, David L Farrens

Abstract read
In one paragraph

Article in Biophysical journal, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

1 citing paper in PubMed.

  1. Review
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

3 authors.

Weekie YaoDepartment of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, Oregon 97239.
Adam C OkenDepartment of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, Oregon 97239.
David L FarrensDepartment of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, Oregon 97239. Electronic address: farrensd@ohsu.edu.

Funding

Pacific Northwest Center for Cryo-EM - Screening supplementU24GM129547 · NIGMS · OREGON HEALTH & SCIENCE UNIVERSITY · PI EVANS, JAMES E, GOUAUX, JAMES E · 2018 to 2023
$54.8M
Structural Dynamics in Rhodopsin Activation and AttenuationR01EY029343 · NEI · OREGON HEALTH & SCIENCE UNIVERSITY · PI David L Farrens · 2019 to 2026
$2.9M
NEI NIH HHS R01 EY029343NIGMS NIH HHS U24 GM129547
6 · The paper itself

Abstract

Small proteins can be challenging to study by single-particle cryogenic electron microscopy (cryo-EM) techniques because they have low signal-to-noise ratios, making them difficult to identify and analyze. Here we investigated the use of Csp1, a small (∼50 kDa) tetrameric metal-binding protein, to act as a "bio-tag" to help overcome this problem. We find Csp1 is compact, stable, and exhibits enhanced electron scattering and excellent particle contrast in cryo-EM micrographs. As a result, we could determine the structure of Csp1 to 2.98-Å resolution using standard cryo-EM approaches. We also tested if Csp1 could be used as a tag or fiducial to help determine the structure of a protein bound to it. Specifically, we analyzed an epitope-tagged Csp1 bound to a ∼40 kDa Fab fragment from the antibody 1D4. Data from these complexes yielded medium-resolution structures of the complex (5.70 Å) and the bound 1D4 Fab (5.40 Å). These results suggest that, with further optimization, electron-rich Csp1 is a promising bio-tag for use in cryo-EM studies.

Indexed as

Cryoelectron MicroscopyEscherichia coli ProteinsImmunoglobulin Fab FragmentsModels, MolecularEscherichia coli ProteinsImmunoglobulin Fab Fragments

Identifiers

PMID40620219
PMCPMC12256830

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.