7XGY

cryo-EM structure of hemoglobin

Summary for 7XGY

• Entry DOI: 10.2210/pdb7xgy/pdb
• EMDB information: 33189
• Descriptor: Hemoglobin subunit alpha, Hemoglobin subunit beta, PROTOPORPHYRIN IX CONTAINING FE (3 entities in total)
• Functional Keywords: tetramer, oxygen transport
• Biological source: Homo sapiens (human); More
• Total number of polymer chains: 4
• Total formula weight: 65071.84

Authors

Liu, N.,Wang, H.W. (deposition date: 2022-04-07, release date: 2022-11-09, Last modification date: 2024-07-03)

Primary citation

Zheng, L.,Liu, N.,Gao, X.,Zhu, W.,Liu, K.,Wu, C.,Yan, R.,Zhang, J.,Gao, X.,Yao, Y.,Deng, B.,Xu, J.,Lu, Y.,Liu, Z.,Li, M.,Wei, X.,Wang, H.W.,Peng, H.
Uniform thin ice on ultraflat graphene for high-resolution cryo-EM.
Nat.Methods, 20:123-130, 2023

PubMed Abstract: Cryo-electron microscopy (cryo-EM) visualizes the atomic structure of macromolecules that are embedded in vitrified thin ice at their close-to-native state. However, the homogeneity of ice thickness, a key factor to ensure high image quality, is poorly controlled during specimen preparation and has become one of the main challenges for high-resolution cryo-EM. Here we found that the uniformity of thin ice relies on the surface flatness of the supporting film, and developed a method to use ultraflat graphene (UFG) as the support for cryo-EM specimen preparation to achieve better control of vitreous ice thickness. We show that the uniform thin ice on UFG improves the image quality of vitrified specimens. Using such a method we successfully determined the three-dimensional structures of hemoglobin (64 kDa), α-fetoprotein (67 kDa) with no symmetry, and streptavidin (52 kDa) at a resolution of 3.5 Å, 2.6 Å and 2.2 Å, respectively. Furthermore, our results demonstrate the potential of UFG for the fields of cryo-electron tomography and structure-based drug discovery.

PubMed: 36522503
DOI: 10.1038/s41592-022-01693-y

Experimental method

ELECTRON MICROSCOPY (3.5 Å)