Revisiting SEPT7 and the slippage of beta-strands in the septin family

Author(s)

Brognara, Gabriel ^[1] ; Pereira, Humberto D'Muniz ^[1] ; Brandao-Neto, Jose ^[2] ; Ulian Araujo, Ana Paula ^[1] ; Garratt, Richard Charles ^[1]

Affiliation

^[1] Univ Sao Paulo, Sao Carlos Inst Phys, Ave Joao Dagnone 1100, BR-13563120 Sao Carlos, SP - Brazil

^[2] Diamond Light Source, Harwell Sci & Innovat Campus, Didcot, Oxon - England

• Document type: Journal article
• Source: Journal of Structural Biology; v. 207, n. 1, p. 67-73, JUL 1 2019.
• Web of Science Citations: 0

Abstract

Septins are GTP-binding proteins that will often spontaneously assemble into filaments. In some species, particularly budding yeast, it is well known that these are capable of associating with membranes in order to fulfill their cellular role as a component of the cytoskeleton. Different from other human septins, SEPT7 appears to be unique in that it is an essential component of all hetero-oligomeric complexes described to date. As a step towards understanding the molecular basis of filament assembly, here we present two high-resolution structures of the SEPT7 GTPase domain complexed with GDP. One of these reveals a previously unreported coordination for the magnesium ion involving four water molecules and only a tenuous connection to the protein. The higher resolution structures provide unambiguous insight into the interactions at the G-interface where a structural motif based on an antiparallel beta-bridge allows for the rationalization of why some septins show nucleotide-dependent beta-strand slippage and others do not. (AU)

• FAPESP's process: 14/15546-1 - Septins: comparative studies and the correlation between structure and function
• Grantee: Richard Charles Garratt
• Support Opportunities: Research Projects - Thematic Grants