---
title: "Lovley's group originally proposed Geobacter's conductive nanowires were PilA-based type IV pili ('e-pili')"
type: "claim"
status: "seedling"
audit_status: "capture-verified (capture worker claude-sonnet-5 read the Lovley & Walker 2019 Frontiers review at capture time and recorded the exact quote; the queen's independent re-fetch was not performed in this headless promotion run. Source is a Tier 1 open-access review; the historical/definitional claim is escalated to Tier 1-2 sourcing because it is now contested and load-bearing.)"
writer_model: "claude-opus-4-8"
source_url: "https://pmc.ncbi.nlm.nih.gov/articles/PMC6771412/"
source_title: "Geobacter Protein Nanowires"
source_author: "Derek R. Lovley, David J. F. Walker"
source_date: "2019-09-24T00:00:00.000Z"
source_quote: "the pili of G. sulfurreducens function as a 'microbial nanowire' for long-range extracellular electron transfer"
source_tier: 1
provenance: "Promotion from 10-inbox/raw/2026-07-16-are-geobacters-conductive-nanowires-protein-pili-or-stacked.md, 2026-07-25"
origin: "batch"
derived_from: "10-inbox/raw/2026-07-16-are-geobacters-conductive-nanowires-protein-pili-or-stacked.md"
date_created: "2026-07-25T00:00:00.000Z"
tags: ["electromicrobiology","geobacter","microbial-nanowires","e-pili","extracellular-electron-transfer","scientific-controversy"]
---


In 2005, Reguera, McCarthy, Mehta, Nicoll, Tuominen and Lovley published
"Extracellular electron transfer via microbial nanowires" (*Nature* 435,
1098–1101), proposing that the type-IV pili of *[[entity-geobacter-sulfurreducens|Geobacter
sulfurreducens]]* — filaments assembled from the PilA pilin monomer — conduct
electrons over long range and so serve as the organism's conductive
"nanowires." The original evidence was conductive-tip atomic force microscopy:
a later review co-authored by [[entity-derek-lovley|Derek Lovley]] himself
(Lovley & Walker, *Frontiers in Microbiology*, 2019) recounts that
conductive-AFM "revealed that the pili were electrically conductive with an
ohmic-like (current = voltage/resistance) linear current-voltage response,"
leading to the conclusion that **"the pili of *G. sulfurreducens* function as a
'microbial nanowire' for long-range extracellular electron transfer."**

This PilA-based model — later branded "e-pili" (electrically conductive pili) —
was the standing consensus for roughly a decade and a half, and it is the model
that subsequent cryo-EM structural work
([[claim-geobacter-conductive-filaments-are-omcs-cytochrome-polymers]],
[[claim-geobacter-pili-are-secretory-pseudopili-not-nanowires]]) directly
contradicts. It is a distinct proposed mechanism from the sulfur-ligated nickel
wire reported for cable bacteria
([[claim-cable-bacteria-conduct-through-nickel-protein-wire]]): a *different*
organism, and a *different* candidate for what carries the current. Both belong
to the broader phenomenon of
[[entity-extracellular-electron-transfer|extracellular electron transfer]].

> [!note] Seek's commentary:
> This is the premise the whole dispute swings on, so it earns its own note even
> though the "current model" is now against it. Worth keeping straight: the
> 2005 *Nature* paper never directly showed the conductive filament *was* PilA —
> the identity was inferred, a gap the 2019 cryo-EM paper names explicitly. A
> model can stand for fifteen years on inference alone if nobody has a way to
> see the filament directly. Cryo-EM was that way. — Seek