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R138C

Category 4 — Stable Fold, Function DisruptedConflictingCytoplasmic · predictedEditorial
ArginineCysteine at position 138 · N-terminal cytoplasmic domain (87-313) · WFS1 (Wolframin)

Arginine → Cysteine at position 138 in N-terminal cytoplasmic domain. ClinVar Conflicting including Wolfram syndrome 1. AlphaMissense 0.29 (below threshold) — AM under-call. DynaMut2 ΔΔG -0.72. R→C class.

Interactive 3D Structure

Wild-type reference
Wild-type R138 — hydrogen bond to V142
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DynaMut2 mutant · R138C
Mutant C138 — hydrogen bond to A141 lost (7 contacts lost)
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Bond changes · DynaMut2 interaction analysis

7 lost1 gained7 preserved
Interaction typeWild-type partnerMutant partnerStatus
Hydrogen bondP100Lost
Hydrogen bondA133A133Preserved
Hydrogen bondE140Gained
Hydrogen bondA141A141Preserved
Hydrogen bondV142V142Preserved
Polar contactP100Lost
Polar contactT104Lost
Polar contactA133A133Preserved
Polar contactE140Lost
Polar contactA141Lost
Polar contactV142V142Preserved
Van der WaalsK101Lost
Van der WaalsA133A133Preserved
HydrophobicA133Lost
HydrophobicA141A141Preserved

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
-0.72kcal/mol
Destabilising — mild
AlphaMissense
0.289
LBen
AlphaFold pLDDT
89
model confidence
Schema
Cat 4
Category 4 — Stable Fold, Function Disrupted

Clinical Evidence

ClinVar classificationConflicting classifications of pathogenicity
Review statuscriteria provided, conflicting classifications
Associated conditionsWolfram syndrome 1
InheritanceWolfram syndrome 1.
Population frequency (gnomAD v4)Ultra-rare · AF 0.0010%
cDNA changec.412C>T
ClinVar accessionVCV001000139
Last evaluated2025/03/17 00:00

Observed at very low frequency in gnomAD.

Structural Context

Position 138 in N-term. Neighbors: ARG139 (2.5 Å — adjacent existing arginine), GLY137 (2.5 Å), ALA133 (3.8 Å — A133T position). The wild-type R138 sits adjacent to R139 — two consecutive arginines in the cytoplasmic domain.

R138C eliminates one of the two adjacent positives and introduces a free thiol. In cytosol, the thiol is less reactive than in ER lumen but can still participate in glutathionylation or regulatory thiol chemistry. AM 0.29 under-call; Wolfram 1 confirms pathogenicity.

Amino-acid chemistry
Arginine (R) → Cysteine (C) — long positively-charged guanidinium replaced by short thiol.
Position in the protein
N-terminal cytoplasmic domain · position 138 (pLDDT 89).

Druggability Assessment

Category 3/4 — Most Druggable (AM under-call). |ΔΔG| 0.72. AlphaMissense 0.29 below threshold but Wolfram 1 confirms pathogenicity.

Mechanism: charge loss from R138-R139 cluster + thiol introduction. Therapeutic: same N-term microregion (with A133T adjacent).

Why this matters

R138C joins the R→C class (now 8+ variants) and the 133-138 cytoplasmic cluster.
Therapeutic Strategy Handoff · prediction

Feed this card to Wolfram Intelligence

Download the R138C 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 R138C PDF card ↓Strategies are AI-generated predictions, not validated therapeutics.

UniProt Domain Annotation

Chain1890 · Wolframin
Region1321 · Interaction with ATP6V1A