8EW5

The structure of flightin within myosin thick filaments from Bombus ignitus flight muscle

Summary for 8EW5

• Entry DOI: 10.2210/pdb8ew5/pdb
• EMDB information: 28208
• Descriptor: Flightin (1 entity in total)
• Functional Keywords: striated muscle, regulatory protein, myosin-binding protein, structural protein
• Biological source: Bombus ignitus
• Total number of polymer chains: 1
• Total formula weight: 18396.54

Authors

Li, J.,Rahmani, H.,Abbasi Yeganeh, F.,Rastegarpouyani, H.,Taylor, D.W.,Wood, N.B.,Previs, M.J.,Iwamoto, H.,Taylor, K.A. (deposition date: 2022-10-21, release date: 2023-01-04, Last modification date: 2025-05-21)

Primary citation

Li, J.,Rahmani, H.,Abbasi Yeganeh, F.,Rastegarpouyani, H.,Taylor, D.W.,Wood, N.B.,Previs, M.J.,Iwamoto, H.,Taylor, K.A.
Structure of the Flight Muscle Thick Filament from the Bumble Bee, Bombus ignitus , at 6 angstrom Resolution.
Int J Mol Sci, 24:-, 2022

PubMed Abstract: Four insect orders have flight muscles that are both asynchronous and indirect; they are asynchronous in that the wingbeat frequency is decoupled from the frequency of nervous stimulation and indirect in that the muscles attach to the thoracic exoskeleton instead of directly to the wing. Flight muscle thick filaments from two orders, Hemiptera and Diptera, have been imaged at a subnanometer resolution, both of which revealed a myosin tail arrangement referred to as “curved molecular crystalline layers”. Here, we report a thick filament structure from the indirect flight muscles of a third insect order, Hymenoptera, the Asian bumble bee Bombus ignitus. The myosin tails are in general agreement with previous determinations from Lethocerus indicus and Drosophila melanogaster. The Skip 2 region has the same unusual structure as found in Lethocerus indicus thick filaments, an α-helix discontinuity is also seen at Skip 4, but the orientation of the Skip 1 region on the surface of the backbone is less angled with respect to the filament axis than in the other two species. The heads are disordered as in Drosophila, but we observe no non-myosin proteins on the backbone surface that might prohibit the ordering of myosin heads onto the thick filament backbone. There are strong structural similarities among the three species in their non-myosin proteins within the backbone that suggest how one previously unassigned density in Lethocerus might be assigned. Overall, the structure conforms to the previously observed pattern of high similarity in the myosin tail arrangement, but differences in the non-myosin proteins.

PubMed: 36613818
DOI: 10.3390/ijms24010377

Experimental method

ELECTRON MICROSCOPY (6 Å)