This site hosts a suite of tools for the study of four-residue (beta) turns, which are the most common local ("secondary") structures in proteins after alpha helices and beta sheets and play key structural and functional roles (see below). ExploreTurns [1] is a facility for the comprehensive exploration, analysis, geometric tuning and retrieval of beta turns and their backbone (BB) and side-chain (SC) motifs and contexts from a redundancy-screened, PDB-derived database of 102,192 turns. Since beta turns constitute close to two-thirds of protein loops, and ExploreTurns also encompasses the four-residue N-/C-terminal neighborhoods of turns, the facility serves as a browser and analysis tool for most loop structure, supported by a built-in interpreter for a new nomenclature that classifies all short H-bonded loops. The second tool, MapTurns [2], is a server for motif maps, which are interactive, 3D graphical conformational heatmaps of the BB and SC structure, H-bonding and contexts associated with sequence motifs in beta turns. Maps support mutational analysis, the general study of SC interactions, and detailed structural rationalizations of sequence preferences. The last tool, ProfileTurn, profiles the geometry and sequence motifs of a turn uploaded by the user and supports browsing the principal recurrent BB conformations of turns. These tools incorporate a new turn-local Euclidean-space coordinate system and a global turn alignment, along with geometric turn parameters [3] that complement Ramachandran-space turn classification systems, and extensive online help is provided. For best performance, browse with Chrome or Edge.

Explore, profile, tune and retrieve beta turns and their motifs and contexts.

Map the structure, H-bonding and contexts associated with sequence motifs in beta turns.

Upload a beta turn and profile its geometry and sequence motif content.

View a poster describing ExploreTurns and MapTurns presented at the Protein Society's 37th Annual Symposium on July 13-16, 2023 in Boston (new features have since been added to the tools).

An overview of key roles played by beta turns in proteins.

1)   Newell, NE. ExploreTurns: a web tool for the exploration and analysis of beta turns and their contexts in proteins; application to beta-bulge and Schellman loops, Asx helix caps and other hydrogen-bonded motifs. bioRxiv. doi: https://doi.org/10.1101/2024.01.01.573820

2)   Newell, NE. MapTurns: mapping the structure, H-bonding and contexts of beta turns in proteins. bioRxiv. doi: https://doi.org/10.1101/2024.01.02.573949

3)   Newell, NE. A geometric parameterization for beta turns. bioRxiv. doi: https://doi.org/10.1101/2024.01.01.573818