6ZZB

Crystal structure of the Eimeria tenella surface antigen protein SAG19

6ZZB の概要

• エントリーDOI: 10.2210/pdb6zzb/pdb
• 分子名称: SAG family member (Sag19), SULFATE ION (3 entities in total)
• 機能のキーワード: apicomplexa, eimeria tenella, cap proteins, sag19, unknown function
• 由来する生物種: Eimeria tenella (Coccidian parasite)
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 26282.13

構造登録者

Dix, S.R.,Rice, D.W. (登録日: 2020-08-04, 公開日: 2021-03-24, 最終更新日: 2024-10-23)

主引用文献

Ramly, N.Z.,Dix, S.R.,Ruzheinikov, S.N.,Sedelnikova, S.E.,Baker, P.J.,Chow, Y.P.,Tomley, F.M.,Blake, D.P.,Wan, K.L.,Nathan, S.,Rice, D.W.
The structure of a major surface antigen SAG19 from Eimeria tenella unifies the Eimeria SAG family.
Commun Biol, 4:376-376, 2021

PubMed Abstract: In infections by apicomplexan parasites including Plasmodium, Toxoplasma gondii, and Eimeria, host interactions are mediated by proteins including families of membrane-anchored cysteine-rich surface antigens (SAGs) and SAG-related sequences (SRS). Eimeria tenella causes caecal coccidiosis in chickens and has a SAG family with over 80 members making up 1% of the proteome. We have solved the structure of a representative E. tenella SAG, EtSAG19, revealing that, despite a low level of sequence similarity, the entire Eimeria SAG family is unified by its three-layer αβα fold which is related to that of the CAP superfamily. Furthermore, sequence comparisons show that the Eimeria SAG fold is conserved in surface antigens of the human coccidial parasite Cyclospora cayetanensis but this fold is unrelated to that of the SAGs/SRS proteins expressed in other apicomplexans including Plasmodium species and the cyst-forming coccidia Toxoplasma gondii, Neospora caninum and Besnoitia besnoiti. However, despite having very different structures, Consurf analysis showed that Eimeria SAG and Toxoplasma SRS families each exhibit marked hotspots of sequence hypervariability that map to their surfaces distal to the membrane anchor. This suggests that the primary and convergent purpose of the different structures is to provide a platform onto which sequence variability can be imposed.

PubMed: 33742128
DOI: 10.1038/s42003-021-01904-w

実験手法

X-RAY DIFFRACTION (1.322 Å)