Extended Data Fig. 3: RbCBM26 shares a conserved binding site with other CBM26. | Nature Structural & Molecular Biology

Extended Data Fig. 3: RbCBM26 shares a conserved binding site with other CBM26.

From: The Ruminococcus bromii amylosome protein Sas6 binds single and double helical α-glucan structures in starch

Extended Data Fig. 3

The top structural homologs of RbCBM26 from DALI36,42 are the CBM25 from Bacillus halodurans C-125 (BhCBM25) from α-amylase G-6 (PDB ID: 2C3V-A, Z-score: 12.4, RMSD 1.9Å, identity: 16%) and CBM26 (BhCBM26) from the same enzyme (PDB ID: 6B3P-B, Z-score: 12.1, RMSD 1.9Å, identity: 20%)41. Another top DALI result is ErCBM26b of Amy13K from Eubacterium rectale (PDB ID 2C3H-B, Z-score: 10.8, RMSD 1.7Å, identity: 19%)43. a. Sequence alignment of RbCBM26 (RBL236_00020), ErCBM26 (ERE_20420), BhCBM26 (BH0413), and LaCBM26 (Q48502). Conserved binding site residues are indicated by a red arrow while variable residues are indicated by a blue arrow and provide hydrogen bonding. b. Overlay of RbCBM26 (green) with BhCBM26 (PDB 2c3h, orange), and ErCBM26 (PDB 6b3p, purple). c. Overlay of unliganded RbCBM26 (blue) and ACX-bound RbCBM26 (green) showing that loop 1 does not move upon ligand binding. b-strands are numbered for reference.

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