2024-10-23 REL PDBe PDBe PDBe 2024-03-21 2024-07-17 2024-07-17 2024-10-23 Not funded Grossman-Haham I Shahar A archaellum, haloarcheon, archaellin, STRUCTURAL PROTEIN Sofer S Vershinin Z Mashni L Zalk R Shahar A Eichler J Grossman-Haham I Nat Commun UK 15 5841 5841 2024 38992036 doi:10.1038/s41467-024-50277-1 2041-1723 9eq7 FULLOVERLAP Archaellum filament Archaellum filament 0 1 Halobacterium salinarum 0.0215 Archaellin Halobacterium salinarum 0.020107971

Since Hbt. salinarum encodes five archaellins (i.e., FlaA1, FlaA2, FlaB1, FlaB2, and FlaB3) and their arrangement within the archaellum filaments is unknown, we further refined the cryo-EM map without applying symmetry, in an attempt to resolve the positions of these archaellins within the filament, as done previously with reconstruction of the Methanocaldococcus villosus archaellum. Symmetry-free refinement improved the overall resolution map to 3.1 A and revealed differences in density among archaellin subunits. Nonetheless, we were unable to identify features that would allow us to unambiguously assign specific archaellins into the density, perhaps because the regions that distinguish each archaellin are few, short, and mostly predicted to lack defined secondary structure, or because the five archaellins are not organized in a repeating pattern. Consequently, we built a model into the central region of the cryo-EM map comprising 26 archaellin subunits that share a consensus sequence, in which identical residues among the five archaellins are explicitly modelled, with those variable residues usually being modelled as alanine residues (UNK).

26 LEVO MFEFITDEDERGQVGIGTLIVFIAMVLVAAIAAGVLINTAGYLQSKGSATGEEASAQVSNRINIVSAYGNV(UNK) (UNK)(UNK)(UNK)VDYVNLTVRQAAGADNINL(UNK)KSTIQWIGPD(UNK)ATTLTY(UNK)(UNK)(UNK)(UNK) (UNK)(UNK)(UNK)(UNK)(UNK)ENFTT(UNK)SIKG(UNK)(UNK)(UNK)(UNK)VLVDQSDRIKVIMYA(UNK) (UNK)V(UNK)(UNK)(UNK)L(UNK)(UNK)G(UNK)EVQLTVTTQYGSKTTYWAQVPESLKDKNAV(UNK)L helical filament 7.5 250.0 NaCl Sodium Chloride 20.0 MgSO4*7H2O Magnesium Sulfate 3.0 Na3C6H5O7 sodium citrate ETHANE TFS GLACIOS SPOT SCAN OTHER FIELD EMISSION GUN 200 0.5 1.5 FEI FALCON IV (4k x 4k) 30.0 1 5.49 107.95 C1 3.23 FSC 0.143 CUT-OFF 334202 MAXIMUM LIKELIHOOD emd_19905_additional_2.map.gz 1 IMAGE STORED AS FLOATING POINT NUMBER (4 BYTES) 416 416 416 0 0 0 416 416 416 370.24 370.24 370.24 90.0 90.0 90.0 X Y Z -0.028734144 1.9656096 0.0040477766 0.045633286 0.89 0.89 0.89 AUTHOR ::::EMDATABANK.org::::EMD-19905:::: emd_19905_additional_1.map.gz 1 IMAGE STORED AS FLOATING POINT NUMBER (4 BYTES) 416 416 416 0 0 0 416 416 416 370.24 370.24 370.24 90.0 90.0 90.0 X Y Z -0.10966464 17.391752 0.059915617 0.7893757 0.89 0.89 0.89 AUTHOR ::::EMDATABANK.org::::EMD-19905:::: emd_19905_half_map_2.map.gz 1 IMAGE STORED AS FLOATING POINT NUMBER (4 BYTES) 416 416 416 0 0 0 416 416 416 370.24 370.24 370.24 90.0 90.0 90.0 X Y Z -0.34142008 0.5246179 0.000620836 0.038571313 0.89 0.89 0.89 AUTHOR ::::EMDATABANK.org::::EMD-19905:::: emd_19905_half_map_1.map.gz 1 IMAGE STORED AS FLOATING POINT NUMBER (4 BYTES) 416 416 416 0 0 0 416 416 416 370.24 370.24 370.24 90.0 90.0 90.0 X Y Z -0.3455544 0.52586335 0.00060703495 0.038724415 0.89 0.89 0.89 AUTHOR ::::EMDATABANK.org::::EMD-19905::::