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T337I

Category 3/4 — Most DruggableLikely pathogenicTransmembrane · predictedEditorial
ThreonineIsoleucine at position 337 · Connecting loop · WFS1 (Wolframin)

Threonine → Isoleucine at position 337 in a connecting loop. ClinVar Likely pathogenic for Wolfram syndrome 1. AlphaMissense 0.865, DynaMut2 ΔΔG -0.48 kcal/mol (destabilising). pLDDT 65 borderline.

Interactive 3D Structure

Wild-type reference
Wild-type T337 — hydrogen bond to N335
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DynaMut2 mutant · T337I
Mutant I337 — hydrogen bond to F340 lost (2 contacts lost)
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Bond changes · DynaMut2 interaction analysis

2 lost2 gained7 preserved
Interaction typeWild-type partnerMutant partnerStatus
Hydrogen bondN335N335Preserved
Hydrogen bondF340F340Preserved
Hydrogen bondF341F341Preserved
Polar contactN335N335Preserved
Polar contactD339D339Preserved
Polar contactF340F340Preserved
Polar contactF341F341Preserved
Van der WaalsN335Gained
Van der WaalsF340Lost
Van der WaalsF341Lost
HydrophobicD339Gained

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
-0.48kcal/mol
Destabilising — mild
AlphaMissense
0.865
LPath
AlphaFold pLDDT
65
model confidence
Schema
Cat 3/4
Category 3/4 — Most Druggable

Clinical Evidence

ClinVar classificationLikely pathogenic
Review statuscriteria provided, multiple submitters, no conflicts
Associated conditionsWolfram syndrome 1
InheritanceWolfram syndrome 1 (AR) documented.
Population frequency (gnomAD v4)Absent from gnomAD v4
cDNA changec.1010C>T
ClinVar accessionVCV002203515
Last evaluated2025/08/26 00:00

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

Structural Context

Position 337 sits in a connecting loop near TM2. The AlphaFold model places T337 within 5 Å of ILE338 (2.4 Å), LEU336 (2.5 Å), ASN335 (4.1 Å), ASP339 (4.2 Å), and PHE340 (4.4 Å). The local environment is mixed polar-hydrophobic.

The wild-type threonine's hydroxyl likely H-bonds with the nearby N335 or D339. Replacing it with isoleucine eliminates the H-bonding capacity. The fold absorbs the substitution (|ΔΔG| 0.48), but the local H-bond network reorganizes.

AlphaMissense 0.865 + Wolfram 1 confirm pathogenic consequence. The mechanism is loss of T337's H-bonding role in the loop's polar network. pLDDT 65 is borderline; structural details deserve wet-lab confirmation.

Amino-acid chemistry
Threonine (T) → Isoleucine (I) — small polar hydroxyl replaced by branched aliphatic hydrophobic. Loss of H-bonding.
Position in the protein
Connecting loop · position 337 in a borderline-confidence region (pLDDT 65).

Druggability Assessment

Category 3/4 — Most Druggable (pLDDT caveat). |ΔΔG| = 0.48 — fold survives. AlphaMissense 0.865 + Wolfram 1 confirm pathogenic consequence. pLDDT 65 borderline.

Mechanism is loss of T337 H-bonding role. Therapeutic strategy: site-directed at the connecting loop polar network.

Why this matters

T337I is another threonine-to-isoleucine variant in the Atlas (with T361I). The class of T→I substitutions, removing H-bonding capacity, recurs at multiple positions and is consistently pathogenic.
Therapeutic Strategy Handoff · prediction

Feed this card to Wolfram Intelligence

Download the T337I 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 T337I PDF card ↓Strategies are AI-generated predictions, not validated therapeutics.

UniProt Domain Annotation

Chain1890 · Wolframin