6VZU

TTLL6 bound to alpha-elongation analog

Summary for 6VZU

• Entry DOI: 10.2210/pdb6vzu/pdb
• Descriptor: Tubulin polyglutamylase TTLL6, TTLL6 unregistered chain, GLYCEROL, ... (10 entities in total)
• Functional Keywords: ttll6, glutamylase, amino-acid ligase, phosphinic acid inhibitors, ligase
• Biological source: Mus musculus (Mouse); More
• Total number of polymer chains: 6
• Total formula weight: 221446.40

Authors

Mahalingan, K.K.,Keenen, E.K.,Strickland, M.,Li, Y.,Liu, Y.,Ball, H.B.,Tanner, M.E.,Tjandra, N.,Roll-Mecak, A. (deposition date: 2020-02-28, release date: 2020-08-12, Last modification date: 2023-10-11)

Primary citation

Mahalingan, K.K.,Keith Keenan, E.,Strickland, M.,Li, Y.,Liu, Y.,Ball, H.L.,Tanner, M.E.,Tjandra, N.,Roll-Mecak, A.
Structural basis for polyglutamate chain initiation and elongation by TTLL family enzymes.
Nat.Struct.Mol.Biol., 27:802-813, 2020

PubMed Abstract: Glutamylation, introduced by tubulin tyrosine ligase-like (TTLL) enzymes, is the most abundant modification of brain tubulin. Essential effector proteins read the tubulin glutamylation pattern, and its misregulation causes neurodegeneration. TTLL glutamylases post-translationally add glutamates to internal glutamates in tubulin carboxy-terminal tails (branch initiation, through an isopeptide bond), and additional glutamates can extend these (elongation). TTLLs are thought to specialize in initiation or elongation, but the mechanistic basis for regioselectivity is unknown. We present cocrystal structures of murine TTLL6 bound to tetrahedral intermediate analogs that delineate key active-site residues that make this enzyme an elongase. We show that TTLL4 is exclusively an initiase and, through combined structural and phylogenetic analyses, engineer TTLL6 into a branch-initiating enzyme. TTLL glycylases add glycines post-translationally to internal glutamates, and we find that the same active-site residues discriminate between initiase and elongase glycylases. These active-site specializations of TTLL glutamylases and glycylases ultimately yield the chemical complexity of cellular microtubules.

PubMed: 32747782
DOI: 10.1038/s41594-020-0462-0

Experimental method

X-RAY DIFFRACTION (1.98 Å)