National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
GM122510
米国
引用
ジャーナル: J Am Chem Soc / 年: 2023 タイトル: Hollow Octadecameric Self-Assembly of Collagen-like Peptides. 著者: Le Tracy Yu / Maria C Hancu / Mark A B Kreutzberger / Amy Henrickson / Borries Demeler / Edward H Egelman / Jeffrey D Hartgerink / 要旨: The folding of collagen is a hierarchical process that starts with three peptides associating into the characteristic triple helical fold. Depending on the specific collagen in question, these triple ...The folding of collagen is a hierarchical process that starts with three peptides associating into the characteristic triple helical fold. Depending on the specific collagen in question, these triple helices then assemble into bundles reminiscent of α-helical coiled-coils. Unlike α-helices, however, the bundling of collagen triple helices is very poorly understood with almost no direct experimental data available. In order to shed light on this critical step of collagen hierarchical assembly, we have examined the collagenous region of complement component 1q. Thirteen synthetic peptides were prepared to dissect the critical regions allowing for its octadecameric self-assembly. We find that short peptides (under 40 amino acids) are able to self-assemble into specific (ABC) octadecamers. This requires the ABC heterotrimeric composition as the self-assembly subunit, but does not require disulfide bonds. Self-assembly into this octadecamer is aided by short noncollagenous sequences at the N-terminus, although they are not entirely required. The mechanism of self-assembly appears to begin with the very slow formation of the ABC heterotrimeric helix, followed by rapid bundling of triple helices into progressively larger oligomers, terminating in the formation of the (ABC) octadecamer. Cryo-electron microscopy reveals the (ABC) assembly as a remarkable, hollow, crown-like structure with an open channel approximately 18 Å at the narrow end and 30 Å at the wide end. This work helps to illuminate the structure and assembly mechanism of a critical protein in the innate immune system and lays the groundwork for the design of higher order collagen mimetic peptide assemblies.
フィルム・検出器のモデル: GATAN K3 (6k x 4k) / 平均電子線量: 50.0 e/Å2
実験機器
モデル: Titan Krios / 画像提供: FEI Company
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画像解析
初期 角度割当
タイプ: MAXIMUM LIKELIHOOD
最終 角度割当
タイプ: MAXIMUM LIKELIHOOD
最終 再構成
解像度のタイプ: BY AUTHOR / 解像度: 5.0 Å / 解像度の算出法: OTHER 詳細: The 0.143 Map:Map FSC is estimated at 3 Angstrom, but inspection yields a resolution of 5 Angstrom, which is approximately the lowest resolution at which the triple helix is resolvable. 使用した粒子像数: 108000