Diamond Publications - Search Results

Search Again...

These results only include publications that have been reviewed and processed by Diamond Light Source. To also view papers that have not yet been processed click here.

You can use the folder icon under Actions to collate papers as required. You can then click on View Folder in the left-hand navigation to review and/or download your folder.

One item found (0 items not approved).

Instruments / Technical Area	Publication Details	Published	Actions
I02-Macromolecular Crystallography I03-Macromolecular Crystallography	Snapshots during the catalytic cycle of a histidine acid phytase reveal an induced fit structural mechanism Isabella M. Acquistapace , Monika A Ziętek , Arthur W. H. Li , Melissa Salmon , Imke Kühn , Mike R Bedford , Charles A. Brearley , Andrew M. Hemmings Journal Of Biological Chemistry DOI: 10.1074/jbc.RA120.015925 Diamond Proposal Number(s): [7641, 9475, 13467] Show Abstract ▼ Abstract: Highly engineered phytases, which sequentially hydrolyze the hexakisphosphate ester of inositol known as phytic acid, are routinely added to the feeds of monogastric animals to improve phosphate bioavailability. New phytases are sought as starting points to further optimize the rate and extent of dephosphorylation of phytate in the animal digestive tract. Multiple inositol polyphosphate phosphatases (MINPPs) are clade 2 histidine phosphatases (HP2P) able to carry out the stepwise hydrolysis of phytate. MINPPs are not restricted by a strong positional specificity making them attractive targets for development as feed enzymes. Here, we describe the characterization of a MINPP from the Gram-positive bacterium Bifidobacterium longum (BlMINPP). BlMINPP has a typical HP2P fold but, unusually, possesses a large α-domain polypeptide insertion relative to other MINPPs. This insertion, termed the U-loop, spans the active site and contributes to substrate specificity pockets underpopulated in other HP2Ps. Mutagenesis of U-loop residues reveals its contribution to enzyme kinetics and thermostability. Moreover, four crystal structures of the protein along the catalytic cycle capture, for the first time in an HP2P, a large ligand-driven α-domain motion essential to allow substrate access to the active site. This motion recruits residues both downstream of a molecular hinge and on the U-loop to participate in specificity subsites, and mutagenesis identified a mobile lysine residue as a key determinant of positional specificity of the enzyme. Taken together, this data provides important new insights to the factors determining stability, substrate recognition and the structural mechanism of hydrolysis in this industrially important group of enzymes.	Oct 2020

Instruments / Technical Area

Publication Details

Published

Actions

I02-Macromolecular Crystallography
I03-Macromolecular Crystallography

Snapshots during the catalytic cycle of a histidine acid phytase reveal an induced fit structural mechanism

Isabella M. Acquistapace , Monika A Ziętek , Arthur W. H. Li , Melissa Salmon , Imke Kühn , Mike R Bedford , Charles A. Brearley , Andrew M. Hemmings

Journal Of Biological Chemistry

DOI: 10.1074/jbc.RA120.015925

Diamond Proposal Number(s): [7641, 9475, 13467]

Show Abstract ▼

Oct 2020