7DC5

Crystal structure of fungal antifreeze protein with intermediate activity

Summary for 7DC5

• Entry DOI: 10.2210/pdb7dc5/pdb
• Descriptor: Antifreeze protein, SULFATE ION (3 entities in total)
• Functional Keywords: right-handed beta-helix, beta-solenoid, ice-binding protein, thermal hysteresis protein, ice-structuring protein, antifreeze protein
• Biological source: Typhula ishikariensis (Gray snow mold fungus)
• Total number of polymer chains: 2
• Total formula weight: 44631.86

Authors

Khan, N.M.M.U.,Arai, T.,Tsuda, S.,Kondo, H. (deposition date: 2020-10-23, release date: 2021-10-27, Last modification date: 2023-11-29)

Primary citation

Khan, N.M.U.,Arai, T.,Tsuda, S.,Kondo, H.
Characterization of microbial antifreeze protein with intermediate activity suggests that a bound-water network is essential for hyperactivity.
Sci Rep, 11:5971-5971, 2021

PubMed Abstract: Antifreeze proteins (AFPs) inhibit ice growth by adsorbing onto specific ice planes. Microbial AFPs show diverse antifreeze activity and ice plane specificity, while sharing a common molecular scaffold. To probe the molecular mechanisms responsible for AFP activity, we here characterized the antifreeze activity and crystal structure of TisAFP7 from the snow mold fungus Typhula ishikariensis. TisAFP7 exhibited intermediate activity, with the ability to bind the basal plane, compared with a hyperactive isoform TisAFP8 and a moderately active isoform TisAFP6. Analysis of the TisAFP7 crystal structure revealed a bound-water network arranged in a zigzag pattern on the surface of the protein's ice-binding site (IBS). While the three AFP isoforms shared the water network pattern, the network on TisAFP7 IBS was not extensive, which was likely related to its intermediate activity. Analysis of the TisAFP7 crystal structure also revealed the presence of additional water molecules that form a ring-like network surrounding the hydrophobic side chain of a crucial IBS phenylalanine, which might be responsible for the increased adsorption of AFP molecule onto the basal plane. Based on these observations, we propose that the extended water network and hydrophobic hydration at IBS together determine the TisAFP activity.

PubMed: 33727595
DOI: 10.1038/s41598-021-85559-x

Experimental method

X-RAY DIFFRACTION (1.54 Å)