PDBsum entry 6pkt

Hydrolase

PDB id: 6pkt

Contents

Protein chain

279 a.a.

Waters ×150

PDB id:

6pkt

Name:

Hydrolase

Title:

Microed structure of proteinase k from merging low-dose, platinum pre- coated lamellae at 1.85a resolution (ldpt)

Structure:

Proteinase k. Chain: a. Fragment: unp residues 106-384. Synonym: endopeptidase k, tritirachium alkaline proteinase. Ec: 3.4.21.64

Source:

Parengyodontium album. Engyodontium album, tritirachium album. Organism_taxid: 37998

Authors:

M.W.Martynowycz,W.Zhao,J.Hattne,G.J.Jensen,T.Gonen

Key ref:

M.W.Martynowycz et al. (2019). Qualitative Analyses of Polishing and Precoating FIB Milled Crystals for MicroED. Structure, 27, 1594. PubMed id: 31422911 DOI: 10.1016/j.str.2019.07.004

Date:

29-Jun-19 Release date: 04-Sep-19

Protein chain

P06873  (PRTK_PARAQ) -  Proteinase K from Parengyodontium album

Seq: 384 a.a.

Struc: 279 a.a.

Enzyme reactions

• Enzyme class: E.C.3.4.21.64 - peptidase K.
• Reaction: Hydrolysis of keratin and of other proteins, with subtilisin-like specificity. Hydrolyzes peptides amides.

DOI no: 10.1016/j.str.2019.07.004

Structure 27:1594 (2019)

PubMed id: 31422911

Qualitative Analyses of Polishing and Precoating FIB Milled Crystals for MicroED.

M.W.Martynowycz, W.Zhao, J.Hattne, G.J.Jensen, T.Gonen.

ABSTRACT

Microcrystal electron diffraction (MicroED) leverages the strong interaction between matter and electrons to determine protein structures from vanishingly small crystals. This strong interaction limits the thickness of crystals that can be investigated by MicroED, mainly due to absorption. Recent studies have demonstrated that focused ion-beam (FIB) milling can thin crystals into ideal-sized lamellae; however, it is not clear how to best apply FIB milling for MicroED. Here, the effects of polishing the lamellae, whereby the last few nanometers are milled away using a low-current gallium beam, are explored in both the platinum-precoated and uncoated samples. Our results suggest that precoating samples with a thin layer of platinum followed by polishing the crystal surfaces prior to data collection consistently led to superior results as indicated by higher signal-to-noise ratio, higher resolution, and better refinement statistics. This study lays the foundation for routine and reproducible methodology for sample preparation in MicroED.