J 2020

Demonstration of electron diffraction from membrane protein crystals grown in a lipidic mesophase after lamella preparation by focused ion beam milling at cryogenic temperatures

POLOVINKIN, V., K. KHAKUREL, Michal BABIAK, B. ANGELOV, B. SCHNEIDER et. al.

Základní údaje

Originální název

Demonstration of electron diffraction from membrane protein crystals grown in a lipidic mesophase after lamella preparation by focused ion beam milling at cryogenic temperatures

Autoři

POLOVINKIN, V., K. KHAKUREL, Michal BABIAK (703 Slovensko, garant, domácí), B. ANGELOV, B. SCHNEIDER, J. DOHNALEK, J. ANDREASSON a J. HAJDU

Vydání

Journal of Applied Crystallography, Chester, INT UNION CRYSTALLOGRAPHY, 2020, 0021-8898

Další údaje

Jazyk

angličtina

Typ výsledku

Článek v odborném periodiku

Obor

10402 Inorganic and nuclear chemistry

Stát vydavatele

Velká Británie a Severní Irsko

Utajení

není předmětem státního či obchodního tajemství

Odkazy

Impakt faktor

Impact factor: 3.304

Kód RIV

RIV/00216224:14740/20:00118258

Organizační jednotka

Středoevropský technologický institut

UT WoS

000595702500002

Klíčová slova anglicky

electron diffraction; membrane protein crystals grown in meso; lipidic cubic phases; focused ion beam milling; lamella preparation

Štítky

Příznaky

Mezinárodní význam, Recenzováno
Změněno: 27. 10. 2024 14:42, Ing. Martina Blahová

Anotace

V originále

Electron crystallography of sub-micrometre-sized 3D protein crystals has emerged recently as a valuable field of structural biology. In meso crystallization methods, utilizing lipidic mesophases, particularly lipidic cubic phases (LCPs), can produce high-quality 3D crystals of membrane proteins (MPs). A major step towards realizing 3D electron crystallography of MP crystals, grown in meso, is to demonstrate electron diffraction from such crystals. The first task is to remove the viscous and sticky lipidic matrix that surrounds the crystals without damaging the crystals. Additionally, the crystals have to be thin enough to let electrons traverse them without significant multiple scattering. In the present work, the concept that focused ion beam milling at cryogenic temperatures (cryo-FIB milling) can be used to remove excess host lipidic mesophase matrix is experimentally verified, and then the crystals are thinned to a thickness suitable for electron diffraction. In this study, bacteriorhodopsin (BR) crystals grown in a lipidic cubic mesophase of monoolein were used as a model system. LCP from a part of a hexagon-shaped plate-like BR crystal (similar to 10 mu m in thickness and similar to 70 mu m in the longest dimension), which was flash-frozen in liquid nitrogen, was milled away with a gallium FIB under cryogenic conditions, and a part of the crystal itself was thinned into a similar to 210 nm-thick lamella with the ion beam. The frozen sample was then transferred into an electron cryo-microscope, and a nanovolume of similar to 1400 x 1400 x 210 nm of the BR lamella was exposed to 200kV electrons at a fluence of similar to 0.06 e angstrom(-2). The resulting electron diffraction peaks were detected beyond 2.7 angstrom resolution (with an average peak height to background ratio of >2) by a CMOS-based Ceta 16M camera. The results demonstrate that cryo-FIB milling produces high-quality lamellae from crystals grown in lipidic mesophases and pave the way for 3D electron crystallography on crystals grown or embedded in highly viscous media.

Návaznosti

LM2015043, projekt VaV
Název: Česká infrastruktura pro integrativní strukturní biologii (Akronym: CIISB)
Investor: Ministerstvo školství, mládeže a tělovýchovy ČR, Czech Infrastructure for Integrative Structural Biology