# University of Warsaw finds natural proteins tied into 8_3 knots

- Published: 2026-11-07 14:54 UTC
- Section: Life & Health › Biology & biochemistry
- Tags: University of Warsaw, protein knot, EIGHT fold, AlphaFold, Joanna Sulkowska, PNAS, topology
- URL: https://realtech.media/news/rt-44677bd2aba04f37678597d5_university_of_warsaw/

**Researchers identified bacterial proteins with eight chain crossings, confirming predictions made by AlphaFold.**

![University of Warsaw finds natural proteins tied into 8_3 knots](https://realtech.media/media/2026/11/bc5ba1a10bf185bd.jpg)
*Bennettscience, Wikimedia Commons, CC BY 2.0*

A research team led by Joanna Sułkowska from the Centre of New Technologies at the University of Warsaw confirmed the existence of naturally occurring proteins featuring an 8_3 knot, reporting the findings in PNAS, according to zero [1]. The structure contains eight chain crossings, making it the most complex knot identified in nature to date [1]. The newly described group of molecules was designated as the EIGHT fold family, an abbreviation for Extraordinarily Intricate Globular Helical Tangled fold [1].

## Knot verification

The existence of this topology was originally calculated by the predictive algorithm AlphaFold [1]. Prior folding hypotheses assumed that such arrangements could not form because they require threading a terminal segment twice, whereas known biological knots rely on a single threading step [1]. Despite earlier theoretical restrictions, the researchers sought the predicted structures in anaerobic bacteria inhabiting the human gut [1]. After isolating the bacteria and producing the target protein, the team experimentally solved its molecular structure, which matched the algorithmic model [1].

## Unfolding kinetics

Laboratory tests demonstrated that untangling this molecular structure proceeds through six separate stages and requires 72 hours [1]. Sułkowska noted that this represents the most intricate unfolding mechanism documented in scientific literature, yet the duration remains within normal biological bounds [1]. Knotted configurations account for 0.4% of known protein types, representing up to 600 thousand varieties across living systems [1]. How ribosomes achieve the required double threading during synthesis remains unobserved [1].

## Sources

1. [zero](https://zero.pl/news/nie-mial-prawa-istniec-poczatkowo-polscy-naukowcy-mysleli-ze-ai-sie-pomylila)

---

Source: RealTech, realtech.media — https://realtech.media/news/rt-44677bd2aba04f37678597d5_university_of_warsaw/