PDBsum entry 6b7t

Fluorescent protein

PDB id: 6b7t

Contents

Protein chains

208 a.a.

Waters ×93

PDB id:

6b7t

Name:

Fluorescent protein

Title:

Truncated strand 10-less green fluorescent protein

Structure:

Green fluorescent protein,green fluorescent protein. Chain: a, b. Engineered: yes. Mutation: yes

Source:

Aequorea victoria. Jellyfish. Organism_taxid: 6100. Gene: gfp. Expressed in: escherichia coli. Expression_system_taxid: 562

Resolution:

1.91Å R-factor: 0.181 R-free: 0.209

Authors:

A.Deng,S.G.Boxer

Key ref:

A.Deng and S.G.Boxer (2018). Structural Insight into the Photochemistry of Split Green Fluorescent Proteins: A Unique Role for a His-Tag. J Am Chem Soc, 140, 375-381. PubMed id: 29193968

Date:

05-Oct-17 Release date: 27-Dec-17

Protein chains

P42212  (GFP_AEQVI) -  Green fluorescent protein from Aequorea victoria

Seq: 238 a.a.

Struc: 208 a.a.*

* PDB and UniProt seqs differ at 20 residue positions (black crosses)

J Am Chem Soc 140:375-381 (2018)

PubMed id: 29193968

Structural Insight into the Photochemistry of Split Green Fluorescent Proteins: A Unique Role for a His-Tag.

A.Deng, S.G.Boxer.

ABSTRACT

Oligohistidine affinity tags (His-tags) are commonly fused to proteins to aid in their purification via metal affinity chromatography. These His-tags are generally assumed to have minimal impact on the properties of the fusion protein, as they have no propensity to form ordered elements, and are small enough not to significantly affect the solubility or size. Here we report structures of two variants of truncated green fluorescent protein (GFP), i.e., split GFP with a β-strand removed, that were found to behave differently in the presence of light. In these structures, the N-terminal His-tag and several neighboring residues play a highly unusual structural and functional role in stabilizing the truncated GFP by substituting as a surrogate β-strand in the groove vacated by the native strand. This finding provides an explanation for the seemingly very different peptide binding and photodissociation properties of split proteins involving β-strands 10 and 11. We show that these truncated GFPs can bind other non-native sequences, and this promiscuity invites the possibility for rational design of sequences optimized for strand binding and photodissociation, both useful for optogenetic applications.