Structural Genomics Platform

QuaDB

The Quadruplex DataBase

Identify, locate and analyse Putative G-Quadruplex and i-Motif forming sequences across genes, promoters, and regulatory regions — directly in your browser.

▶  G-Quadruplex Finder ▶  i-Motif Finder ◈  PathwayDB Atlas ◈  Browse Publications
Explore
GGGTAGGGCGGGTTGGGAAAGGGCGGGTAGGGCGGGTTGGG — CCCATCCCGCCCAACCC — GGGTTAGGGTTAGGGTTAGGG — CCCTAACCCTAACCCTAACCC — G-QUADRUPLEX  ·  i-MOTIF  ·  QUADRUPLEX DATABASE  ·  PGS FINDER  ·  PIS FINDER  ·  KSBS · IIT DELHI  ·  GGGTAGGGCGGGTTGGGAAAGGGCGGGTAGGGCGGGTTGGG — CCCATCCCGCCCAACCC — GGGTTAGGGTTAGGGTTAGGG — CCCTAACCCTAACCCTAACCC — G-QUADRUPLEX  ·  i-MOTIF  ·  QUADRUPLEX DATABASE  ·  PGS FINDER  ·  PIS FINDER  ·  KSBS · IIT DELHI  · 
0
Supported Organisms
0
Analysis Tools
0
Bulk Analysis Tools
Real‑time
Ensembl API Integration
Structural Nucleic Acid Tools

Choose Your Analysis

TWO STRUCTURE CLASSES — FOUR TOOLS — MULTI-GENE BULK MODE
🔬
G-Quadruplex
GQFinder
Putative G-Quadruplex Sequence Detection

Scans genes and sequences for Putative G-Quadruplex forming Sequences (PGS) using G₃₊(N₁₋₇)G₃₊(N₁₋₇)G₃₊(N₁₋₇)G₃₊ pattern recognition across promoter, gene body, and 3′ downstream regions. Fetches live genomic data via Ensembl REST API.

Promoter −1 kb Gene Body 3′ Downstream ML Scoring FASTA Input Export Results
G-Quadruplex structure — human telomeric (PDB 1K8P)
▶  Launch GQFinder ⬡  Bulk Mode
🧬
i-Motif
iMFinder
Putative i-Motif Sequence Detection

Scans genes and sequences for Putative i-Motif forming Sequences (PIS) using C₃₊(N₁₋₇)C₃₊(N₁₋₇)C₃₊(N₁₋₇)C₃₊ pattern recognition. Intercalated motifs form on the complementary strand to G-Quadruplexes, playing crucial roles in gene regulation and chromatin architecture.

Promoter −1 kb Gene Body 3′ Downstream ML Scoring FASTA Input Export Results
i-Motif structure — intramolecular (PDB 1A83)
▶  Launch iMFinder ⬡  Bulk Mode
High-Throughput Mode

Bulk Analysis

MULTI-GENE PARALLEL SCANNING — PASTE A LIST, GET RESULTS FOR ALL
⬡
Bulk Mode
Bulk GQFinder
Multi-gene G-Quadruplex Detection

Submit a list of gene symbols or Ensembl IDs — separated by line or comma — and QuaDB will sequentially query Ensembl, fetch all three genomic regions, and report PGS counts and sequences for every gene in a single run. Ideal for pathway-level or genome-wide screens.

✓ Unlimited gene list (line or comma separated)
✓ Per-gene promoter / body / downstream breakdown
✓ PGS count summary with sequence coordinates
✓ 8 model organisms supported
Pattern G3+(N1-7)G3+(N1-7)G3+(N1-7)G3+
▶  Launch Bulk GQFinder
SAMPLE OUTPUT ●●●
MYC Promoter 4 GQs
MYC Gene Body 12 GQs
KRAS Promoter 3 GQs
TERT 3′ Down 7 GQs
TP53 Gene Body 9 GQs
⬡
Bulk Mode
Bulk iMFinder
Multi-gene i-Motif Detection

Run i-Motif screening across an entire gene panel simultaneously. Input your gene list, select an organism, and receive a structured report showing PIS counts across all three genomic regions for every gene — in one click.

✓ Unlimited gene list (line or comma separated)
✓ Per-gene promoter / body / downstream breakdown
✓ PIS count summary with sequence coordinates
✓ 8 model organisms supported
Pattern C3+(N1-7)C3+(N1-7)C3+(N1-7)C3+
▶  Launch Bulk iMFinder
SAMPLE OUTPUT ●●●
BRCA1 Promoter 5 iMs
BRCA1 Gene Body 18 iMs
EGFR Promoter 6 iMs
VEGFA 3′ Down 2 iMs
HIF1A Gene Body 11 iMs
💡
When to use Bulk Mode?  Use bulk tools when screening entire gene panels, signalling pathways (e.g. all MAPK genes), or curated gene sets for quadruplex-forming potential — saving you from running analyses one gene at a time.
Workflow

How It Works

FROM GENE SYMBOL TO ANNOTATED MOTIF MAP IN SECONDS
STEP 01
🔎
Input Gene

Enter a gene symbol (e.g. MYC, TERT, BRCA1), Ensembl ID, or paste a raw FASTA sequence directly.

STEP 02
🌐
Fetch Sequence

QuaDB queries the Ensembl REST API in real-time, pulling promoter (−1 kb), gene body, and 3′ downstream (+1 kb) sequences.

STEP 03
⚡
Scan & Score

Regex-based pattern matching identifies all PGS/PIS, each scored by a G/C-tract depth and loop composition algorithm.

STEP 04
📊
Visualise & Export

Results rendered as an interactive distribution map and annotated table. Export to TXT for downstream analysis.

Interactive Preview

Motif Recognition

HIGHLIGHTED IN REAL-TIME — HOVER FOR MOTIF TYPE
SEQUENCE PREVIEW — MYC PROMOTER (HOMO SAPIENS)
LIVE DEMO
Loading sequence...
G-Quadruplex Motif (PGS)
i-Motif Motif (PIS)
Hover motif for details
Supported Model Organisms
Homo sapiens
Mus musculus
Rattus norvegicus
Danio rerio
Drosophila melanogaster
Caenorhabditis elegans
Arabidopsis thaliana
Saccharomyces cerevisiae
Homo sapiens
Mus musculus
Rattus norvegicus
Danio rerio
Drosophila melanogaster
Caenorhabditis elegans
Arabidopsis thaliana
Saccharomyces cerevisiae
◈  PubFetch — PubMed Integration

Explore Quadruplex
Literature

Search curated G-Quadruplex and i-Motif publications from PubMed by gene name and species. Sorted by year, linked directly to original papers.

▶  Fetch Publications
Expanded — Gene Pathway Atlas

Analyse genes by
Pathway & Disease

PathwayDB catalogues 55+ curated human gene sets spanning cancer, signalling, disease, drug targets, and metabolism — with over 1,500 human gene entries. Click any gene for instant live analysis — or run the entire pathway and download a complete GQ & iM results sheet as CSV.

▶  Open PathwayDB ⬇  Bulk CSV Download
55+
Curated Pathways
1500+
Human Gene Entries
Live
Ensembl Analysis
CSV
Bulk Download
Genome-wide Human PQS Resource

Catalogue of Putative Quadruplex Sequences
across the Human Genome

A complete, searchable, downloadable reference of all Putative G-Quadruplex (PGS) and i-Motif (PIS) forming sequences detected across 20,084 human genes by the QuaDB pipeline with per-motif sequences, coordinates, and regional breakdowns for every gene in the human genome.

?  Browse PQS Catalogue ?  Download CSV
20,084
Genes Scanned
PGS
G-Quadruplex Motifs
PIS
i-Motif Sequences
CSV
Bulk Download
© QuaDB — KSBS, IIT Delhi
📽 USER GUIDE