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2395: CACHE SARS Nsp3 followup: Round 5

Closed since about 2 years ago

Intermediate Overall Small Molecule Design

Summary


Created
December 08, 2023
Expires
Max points
100
Description

Compete in a challenge to design a drug targeting the SARS-CoV-2 Nsp3 macrodomain. Use the small molecule design tools and the compound library panel to find library compounds which bind to the active site of the enzyme. -- Only compounds which come from the Compound Library panel and get the Compound Library objective bonus will be experimentally tested.

Note: To get the most out of the small molecule design tools, we recommend changing you view settings to the Small Molecule Design Preset.

This puzzle is part of Foldit's participation in CACHE Challenge #3. We're following up on promising compounds from the first round. For this puzzle series, we're looking to examine the Structure Activity Relationship (SAR) of the hit compounds from the previous series. As such, we ask that you attempt to find things which are similar to the starting molecule, rather than creating something completely new. There's a Similarity objective which should show when you're going too far afield.

We're starting you with the designed structure for this ligand. This isn't necessarily where this compound actually binds, so feel free to move the ligand around in the pocket to find where it (and more importantly derivatives) bind best.

Participation in CACHE puzzles is subject to the CACHE Terms of Participation, in particular “the Challenge IP [including Challenge Compounds] will be made freely available in the public domain pursuant to Creative Commons Attribution Only (CC-BY 4.0 or subsequent versions) licensing terms, with the intent that such Challenge IP may be Used and practiced by Users for any purpose”.

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Comments


rmoretti Staff Lv 1

Objectives

Objectives in this puzzle are driven primarily by the evaluation criteria used by CACHE.

Maximum bonus: +12 000

Similarity (max +1000)

Gives a bonus if the current compound is "similar enough" to the starting (hit) compound. The "percent similarity" being calculated is not quite linear from a visual perspective (search for Tanimoto Similarity for further discussion), and is different from the similarity value being calculated for the Compound Library.

Ligand Identity (max +1000)

In this puzzle series, we're looking for novel ligands. The Ligand Identity objective will give a bonus if you make a ligand which is different from the starting ligand.

Compound Library (max +1000)
Gives a bonus if your current compound is in the library. This uses a local cached version of the Compound Library search results to determine if the compound is in the library. If you manually create a compound that happens to be in the library (or if you load a shared solution with an on-library compound), you may need to submit the compound to the compound library search and wait to get the results back before the objective can properly recognize that the compound is in the library. (If the objective is not updating, try wiggling the structure. See this forum post for more discussion.)

Acid groups (max +1000)
Certain groups like carboxylate and phosphate would make compounds not ideal for drug usage. This gives a bonus if the compound is missing these problematic groups. (Show highlights regions of the molecule at issue.)

Torsion Quality (max +1000)
Keeps bond rotations in a good range. Using Wiggle or Tweak Ligand can fix bad torsions. (Show highlights torsions to be rotated.)

Number of Rotatable Bonds (max +1000)
Intended to keep the ligand from getting too big and floppy. You can reduce rotatable bonds by deleting groups or forming rings. (Show highlights rotatable bonds.)

Ligand TPSA (max +1000)
Topological Polar Surface Area - Keeps the polar surface area (including buried polar surface) low. To improve, try removing oxygens and nitrogens. (Show highlights atoms contributing to higher TPSA.)

Ligand cLogP (max +1000)
A measure of polarity - Keeps the molecule from getting too hydrophobic. To improve, try adding polar oxygens and nitrogens. (Show highlights atoms contributing to higher cLogP.)

Fraction of four-bonded carbons (max +1000)
Measures how carbons with bonds to four atoms ("sp3 hybridized") there are. Too few (too many double and triple bonded carbons) is bad. (Show highlights carbon atoms at issue.)

Bad Groups (max +1000)
Gives a bonus for avoiding groups that interfere with assays, or which are far from the compounds in the library. (Show highlights groups at issue.)

Molecular Weight (max +1000)
Keeps the ligand a reasonable size.

Synthetic Accessibility (max +1000)
Keeps the ligand from going too far from the compounds in the library. (Show highlights parts of the molecule at issue.)

rmoretti Staff Lv 1

The main difference between the puzzles are the starting structures. There's two different compounds, and there's a number of different protein structures. We're hoping the differences in starting structures will result in different final molecules (as slight differences in protein structure can cause different ligand molecules to score highly.)