Structural basis for amyloid fibril assembly by the master cell-signaling regulator receptor-interacting protein kinase 1
From Proteopedia
Structural basis for amyloid fibril assembly by the master cell-signaling regulator receptor-interacting protein kinase 1
| |||||||||||
References
- ↑ PMID:28904096<ref></ref>. In Amyotrophic Lateral Sclerosis, RIPK1, along with RIPK3 and MLKL, has been shown to contribute to the demyelination and degeneration of neurons <ref>PMID:27493188<ref/>. RIPK1 was also linked to an auto-inflammatory syndrome, CRIA syndrome. It is caused by a mutation in RIPK1, which prevents it from being cleaved, leading to uncontrolled cell death and chronic inflammation <ref>PMID:31827281<ref/>. == Structural Determination == The primary methods employed to determine the structure of homomeric RIPK1 fibrils were solid-state NMR and electron microscopy. Cryo-probe detection was used in NMR to increases sensitivity by reducing electronic noise. Negative staining electron microscopy was used to capture initial images, while cryo EM was used for further structural determination. == Structural Highlights == RIPK1 has an N-terminal kinase domain, an intervening disordered region and a C-terminal death domain. The disordered region consists of the RHIM (RIP homotypic interaction motif), which is represented by a tetrapeptide with a consensus sequence of (V/I)-Q-(V/I/L/C)-G. RIPK1 protomers display extended anti-parallel beta-strand architecture, adopting an N-shaped fold within the amyloid core. It consists of three anti-parallel strands, β1 (I529-Y534), β2 (T537-I541), consisting of the RHIM motif and β3 (Y544-I549). β1 and β2 interact via hydrophobic interaction through I531, Y533 and I539 and I541 residues respectively. β2 and β3 establish interaction through a hydrogen bond formed between Q540 and Y546, which is further stabilized by Q540's hydrophobic interactions with M547. Multiple protomers together form the homomeric RIPK1 fibril. The protomers are found in distinct planes along the fibril axis. The fibril forms a left-handed helical structure having a width of 44 Å, a twist of -7.3° and a pitch of 23.3nm. The i protomer can interact with the i+1 and i+2 protomers. The I539 residue of β2 of the i protomer establishes hydrophobic contacts with the Y531 residue of the i+1 and i+2 protomers. Similar interactions are present between I541 and T537 of i protomer and I533 and I549 of i+1 and i+2 protomers. The fibrils also have a ladder of hydrogen bonds that exhibit a stabilizing zipper effect. N545 (β3) of a protomer forms an H-bond with G542 (β2) of the next protomer, locking the β3 of a protomer against the β2 of the next protomer. The N545D mutant showed slower kinetics of fibril formation. This is a sample scene created with SAT to <scene name="/12/3456/Sample/1">color</scene> by Group, and another to make <scene name="/12/3456/Sample/2">a transparent representation</scene> of the protein. You can make your own scenes on SAT starting from scratch or loading and editing one of these sample scenes. </li></ol></ref>
