GlcNAc Man Gal Fuc Neu5Ac SNFG symbols | teaching reconstruction tool

LeGenD Glycan Profiler

Based on Li et al. LeGenD (PMC10996628): reconstruct relative N-glycan abundances on purified proteins from eight lectin-binding signals. This page turns the paper's methods, database construction, and lectin–glycan mapping into a working tool for lectin microarray, ELLA/ELISA, or FACS data.

Why a lectin profile is not a full glycoprofile

Lectins recognize epitopes (local glycan features), such as core fucose, α2,6-sialylated LacNAc, biantennary structures, or bisecting GlcNAc. Figure 1 of the paper simulated lectin signals from 2,912 random glycoprofiles and found that lectin profiles with Pearson R > 0.95 could still map to at least seven distinct N-glycan compositions. The same lectin pattern can therefore correspond to many intact glycan mixtures.

LeGenD (Lectin to Glycoprofile ENhanced with Data-driven methods) does not simply add more lectins. It learns the constraints of glycoprofiles that cells actually produce. The CHO enzyme repertoire, monosaccharide supply, and protein steric limits shrink the possible structure space, so a neural network can map an 8-dimensional lectin vector onto relative abundances of 68 N-glycans.

Lectin array

Many lectins are immobilized on a chip; fluorescent glycoproteins or lysates bind to give a high-throughput RFU map. The paper notes that this format can also use LeGenD, but it needs its own training set.

ELLA / ELISA

The main assay in the paper is an enzyme-linked lectin assay: coat protein in 96-well plates, add biotin-lectin → ABC-HRP → TMB, and read at 450 nm. Signals are background-subtracted and normalized to sum to 1.

FACS

Fluorescent lectins stain the cell-surface glycocalyx; MFI is the binding intensity. The relative lectin vector is the same idea as ELLA, but cell surfaces also carry O-glycans and glycolipids, so interpretation is more cautious.

Original model: 8 lectin inputs → 4 fully connected hidden layers (20 nodes each) → softmax over 68 N-glycan abundances. Best validation RMSE was about 3.60×10−2. SHAP interpretation found LCA and MAL-I most important for IgG. This teaching page cannot ship the unpublished ANN weights, so it uses the paper's Equations 1–2 (glycan-feature matrix × binding-rule matrix) for an interpretable reconstruction, with the same 0.02 denoising threshold.

How the database was built from the paper

The core data gap is that almost no public set has both full UPLC glycoprofiles and experimental lectin profiles on the same samples. The authors therefore used experimental glycoprofiles as ground truth and simulated lectin signals as training inputs, then calibrated with real ELLA of IgG and Fetuin B.

1

Experimental glycoprofiles

30 glycoengineered CHO lines (17 glycosyltransferase knockout/knock-in combinations) produced 10 recombinant proteins. HILIC-UPLC yielded 309 N-glycan profiles and 68 structures.

2

Feature decomposition

Each glycan is counted into LinearCode features: core Fuc, terminal Manα1,2, α2,3/α2,6 Sia, bisecting GlcNAc, β1,6 branching, terminal type-2 LacNAc, and others.

3

Binding rules

Specificities of eight lectins for about ten N-glycan features come from Bojar et al. 2022 (machine-learning annotation of 57 lectins). P-values were converted to z-scores to build the binding-rule matrix (Table S3).

4

Simulated lectin profiles

LP = GP × (feature matrix × binding rules). Linear regression against experimental ELLA of IgG / Fetuin B calibrated the simulation. IgG RMSE = 2.63×10−3; Fetuin B = 3.85×10−3.

5

Training and expansion

The ANN learns simulated lectin → true glycoprofile. Thirty Fetuin-like profiles were also drawn from a Dirichlet distribution (~10% of the training set) to reduce false positives on unseen structures.

Validation proteins (also used as demos here)

Source: Li H, Peralta AG, Schoffelen S, et al. LeGenD: determining N-glycoprofiles using an explainable AI-leveraged model with lectin profiling (bioRxiv 2024; PMC10996628). Binding rules from Bojar et al., ACS Chem. Biol. 2022。

Select an assayed lectin to list matching glycan structures

This table follows Table S1: eight lectins jointly cover about ten common N-glycan features. Click a lectin card or use the dropdown.

Enter lectin array / ELISA / FACS data to reconstruct a glycan profile

Relative intensities are enough. The tool subtracts background if provided and normalizes the lectin vector to sum 1, as in the paper's ELLA processing. Empty lectins are ignored.

Or paste CSV / TSV

Column names may be lectin, signal / intensity / MFI / OD / RFU, plus optional background.

Worked examples (from the paper and common N-glycomes)

Demo lectin signals are simulated from literature-style reference glycoprofiles with the same forward model as the paper, so reconstructions can be compared with the reference mix. This also recreates LeGenD's logic of training on simulated lectin profiles.