T321R

Category 4 — Stable Fold, Function DisruptedLikely pathogenicTransmembrane · predictedEditorial

Threonine → Arginine at position 321 · TM1 (314-334), helical transmembrane · WFS1 (Wolframin)

Threonine → Arginine at position 321 inside TM1. ClinVar Likely pathogenic. AlphaMissense 0.449 (below threshold) — AM under-call. DynaMut2 ΔΔG -0.08 kcal/mol — essentially neutral.

Interactive 3D Structure

Wild-type reference

Wild-type T321 — hydrogen bond to N325

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DynaMut2 mutant · T321R

Mutant R321 — hydrogen bond to I319 lost (2 contacts lost)

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Bond changes · DynaMut2 interaction analysis

2 lost1 gained4 preserved

Interaction type	Wild-type partner	Mutant partner	Status
Hydrogen bond	I319	I319	Preserved
Hydrogen bond	N325	N325	Preserved
Polar contact	I319	I319	Preserved
Polar contact	I324	—	Lost
Polar contact	N325	N325	Preserved
Van der Waals	—	N325	Gained
Hydrophobic	I319	—	Lost

Lost / gained / preserved interatomic contacts at the variant residue, from the DynaMut2 (Arpeggio) interaction analysis of the wild-type and energy-minimized mutant structures.

Computational Predictions

DynaMut2 ΔΔG

-0.08kcal/mol

Destabilising — mild

AlphaMissense

0.449

Amb

AlphaFold pLDDT

model confidence

Schema

Cat 4

Category 4 — Stable Fold, Function Disrupted

Clinical Evidence

ClinVar classificationLikely pathogenic

Review statuscriteria provided, single submitter

Associated conditions(no specific conditions catalogued)

InheritanceInheritance not specified.

Population frequency (gnomAD v4)Absent from gnomAD v4

cDNA changec.962C>G

ClinVar accessionVCV001481097

Last evaluated2025/08/12 00:00

Not observed in ~730k individuals — consistent with a rare allele (ACMG PM2_supporting).

Structural Context

Position 321 sits in TM1, same neighbor environment as T321P (Atlas card adjacent): HIS322 (2.5 Å — partner of H323R and A326E Atlas cards through the H322-H323-A326 cluster), PRO320 (2.5 Å), ILE319 (3.8 Å), ILE324 (4.4 Å), HIS323 (4.5 Å).

Replacing T321 with arginine introduces a large positive charge into the bilayer-embedded TM1. The arginine side chain likely extends toward the membrane-water interface. The H322-H323 cluster nearby is affected by the new positive charge.

The |ΔΔG| of 0.08 (essentially zero) indicates fold accommodates the substitution. AlphaMissense's 0.449 is below threshold — AM under-call. ClinVar Likely Pathogenic establishes clinical relevance. T321R + T321P (same position, different chemistries) both pathogenic confirm position 321 as functionally important.

Amino-acid chemistry

Threonine (T) → Arginine (R) — small polar hydroxyl replaced by large positively-charged guanidinium. Charge introduction into the bilayer.

Position in the protein

TM1 (residues 314–334) · position 321 near the start of TM1 (pLDDT 75).

Druggability Assessment

Category 4 — Stable Fold, Function Disrupted (AM under-call). |ΔΔG| = 0.08 — fold unchanged. AlphaMissense 0.449 below threshold.

Mechanism is charge introduction into TM1. Therapeutic strategy: TM1 microregion site-directed.

Why this matters

T321R + T321P together establish position 321 as a TM1 pathogenic hotspot. Both AM under-calls; both ClinVar pathogenic. Drug discovery here pauses for wet-lab work.

Therapeutic Strategy Handoff · prediction

Feed this card to Wolfram Intelligence

Download the T321R PDF below and upload it to Wolfram Intelligence to generate therapeutic-strategy proposals — guanidinium mimetics, sigma-1 agonist docking, NAC thiol-capping. NAC is already on the bench-testing list.

Download T321R PDF card ↓Strategies are AI-generated predictions, not validated therapeutics.

UniProt Domain Annotation

Chain1–890 · Wolframin

Transmembrane314–334 · Helical

Region1–321 · Interaction with ATP6V1A