We’ve previously shown using all-atom structure representations is a tractable approach to handling biologics (see https://nextmovesoftware.com/blog/2014/11/). Handling biologics in this way allows you to reuse existing registration infrastructure (e.g. Canonical SMILES/InChI/CACTVS keys).
At the Fall ACS ’15, Roger presented an update to this on-going work showing that many popular open-source cheminformatics toolkits can already handle peptides < 500 AA (the size of immunoglobulin heavy chains) in less than a second. We timed the generation of a canonical SMILES string (from the internal representation) over SwissProt. With the exception of Indigo/CDK (that hit hard error limits) the lines stop due to time constraints.
One thing the timings highlighted was recent improvements in RDKit that show faster canonicalisation and and reduced scatter (similar size structures ~ same amount of time). CDK was originally limited by the number of primes listed (it uses product of primes for refinement); patching the CDK to use more primes allows it to encode biopolymers of over 1000 AA.
Roger’s full talk is available here: