Foldit Puzzles

1155: gp120 Design: V3 Hairpin

This protein is a portion of the HIV-1 envelope glycoprotein. The HIV-1 Env protein is a trimer of heterodimers--gp120 (the receptor binding domain) and gp41 (the transmembrane and fusion domain)--and is found on the surface of the HIV-1 virus. The HIV-1 Env complex is responsible for recognizing and binding to a human immune cell through its receptors. When gp120 binds to the human receptors (CD4 and CXCR4 or CXCR5), dramatic conformational changes occur in gp120 and gp41 that cause the virus to fuse with and infect the human cell. This structure of gp120, in a pre-fusion conformation, was recently obtained by x-ray crystallography. However, we know that the V3 loop of gp120 (which exists as a beta-hairpin here) can move in solution, allowing binding of antibodies that will clash with this pre-fusion conformation.

1153: Revisiting Puzzle 97: Pig

This is a throwback puzzle to the early days of Foldit. This saposin protein from pig serves as an activator for lipid-desolving enzymes. This protein contains six cysteines that oxidize to form three disulfide bonds. We are revisiting old Foldit puzzles so we can see how useful the recent additions to the game have been.

1151: Revisiting Puzzle 96: Collagen

This is a throwback puzzle to the early days of Foldit. This small domain is a component of the collagen that forms the connective tissue beneath your skin! This protein contains six cysteines that oxidize to form three disulfide bonds. We are revisiting old Foldit puzzles so we can see how useful the recent additions to the game have been.

1150: 60 Residue Symmetric Dimer Design: Limited HBonds

In this puzzle, the bonus for Hbond networks has been increased, but only Hbond networks that are at least 75% satisfied will be rewarded. Furthermore, no more than three inter-molecular Hbonds may contribute to the filter! There are several other filters in effect; see the puzzle comments for details. The Baker Lab will run folding predictions on your solutions for this puzzle, and those that perform well will be synthesized in the lab. Remember, you can use the Upload for Scientists button for up to 5 designs that you want us to look at, even if they are not the best-scoring solutions!

1149: Revisiting Puzzle 95: Chicken

This is a throwback puzzle to the early days of Foldit. Signals from the nervous system induce Ca²⁺ release within muscle cells. This muscle protein, which normally inhibits muscle contraction, changes shape in the presence of Ca²⁺ to allow muscle contraction. We are revisiting old Foldit puzzles so we can see how useful the recent additions to the game have been.

1148: Unsolved De-novo Freestyle 58: Predicted Contacts

This is a follow-up puzzle for Puzzle 1142 and Puzzle 1145, now with Predicted Contacts to help guide your folding! See the blog for information on using the contact map. You can see the predicted contacts for this protein by clicking the Contact Map button in the Main menu (Selection Interface) or in the Actions tab (Classic Interface). You will notice that different contacts are shown in different shades of green, with brighter green contacts indicating stronger predictions. Players will be able to load in manual saves from Puzzle 1142 or 1145 and use them as a starting point here.

1147: 75 Residue Symmetric Dimer Design: Limited HBonds

Note: Due to a bug with the HBNet filter, this puzzle has been closed and reposted as Puzzle 1147b with a modified filter.

1147b: 75 Residue Symmetric Dimer Design: Satisfied H-Bonds

Note: This puzzle replaces Puzzle 1147 which was closed early due to a bug in the HBNet filter. Players will be able to load in solutions from Puzzle 1147.

1146: Revisiting Puzzle 94: Mouse

This is a throwback puzzle to the early days of Foldit. This protein recruits components of the immune system, and normally keeps white blood cells concentrated in the lymph nodes. However, it also plays a part in the inflammatory response, when immune cells are required to fight an infection. This protein contains four cysteines that oxidize to form two disulfide bonds. We are revisiting old Foldit puzzles so we can see how useful the recent additions to the game have been.

1145: Unsolved De-novo Freestyle 58: Cell Membrane

This is a follow-up puzzle for Puzzle 1142, now with a slightly modified score function. This protein is predicted to be a membrane protein; instead of dissolving in the watery environment of the cytoplasm, this protein resides in the oily environment of the cell membrane. Unlike proteins of typical Foldit puzzles, this protein is likely to have more hydrophobic (orange) residues on the surface, with polar (blue) residues making hydrogen bonds in the protein core. Players will be able to load in manual saves from Puzzle 1142 and use them as a starting point here.