Structural comparison between proteins is key to many
research tasks, including evolutionary analysis,
peptidomimetics, and functional annotation. Traditional
structure alignment tools based on three-dimensional
protein structures, such as TM-Align, DALI, or ProBiS, are
accurate, but they are computationally expensive and
impractical at scale. Existing protein language models
(PLMs), such as TM-Vec, improve computational efficiency
but only capture global structural similarity, overlooking
important motif-level structural details. In this paper, we
propose a novel PLM consisting of a Siamese neural network,
enabling efficient embedding-based structural comparison
while also capturing both global and local structural
similarity. Our model was trained on a dual loss function
combining TM-score, a global similarity metric, and a
variation of lDDT scores, a per-residue similarity metric.
We tested against two datasets: a varied TM-score dataset
from TM-Vec, and a high TM-score mutant dataset from VIPUR.
Against these sets, our model achieved a TM-score MAE of
0.0741 and 0.0583, respectively, and a lDDT-score MAE of
0.0788 and 0.0038, respectively. Our model fulfills two key
roles: first, it rapidly detects global structural
differences. Second, it supports fine-grained structural
assessments, improving sensitivity to subtle but
functionally important structural changes.