9THY

ReAIV structure containing an acrylamide adduct at Cys183 and an orthoborate ester at Ser47

9THY の概要

• エントリーDOI: 10.2210/pdb9thy/pdb
• 関連するPDBエントリー: 8OSW
• 分子名称: L-asparaginase II protein, ZINC ION, CHLORIDE ION, ... (7 entities in total)
• 機能のキーワード: l-asparaginase, acrylamide, zinc metalloenzyme, adduct, microcalorimetry, itc, hydrolase
• 由来する生物種: Rhizobium etli; 詳細
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 73372.67

構造登録者

Sliwiak, J.,Grzechowiak, M.,Worsztynowicz, P.,Pokrywka, K.,Ruszkowski, M.,Gilski, M.,Jaskolski, M. (登録日: 2025-12-04, 公開日: 2026-05-27)

主引用文献

Sliwiak, J.,Grzechowiak, M.,Worsztynowicz, P.,Pokrywka, K.,Ruszkowski, M.,Gilski, M.,Jaskolski, M.
Efficient acrylamide adduct formation suggests dual applications of ReAIV L-asparaginase.
Amino Acids, 2026

PubMed Abstract: Isothermal titration calorimetry (ITC) studies of the enzyme kinetics and substrate specificity of Rhizobium etli Class 3 L-asparaginases, ReAIV (constitutive) and ReAV (inducible), showed that despite highly conserved catalytic site, the two isoforms differ significantly in thermostability, zinc affinity, and biochemical properties. As part of a wider investigation of potential non-natural substrates, acrylamide was tested, revealing a pronounced heat effect with ReAIV but none with ReAV. Crystallographic analysis showed the formation of a Michael adduct between acrylamide and a surface-exposed cysteine 183 in ReAIV, while the catalytic activity toward L-asparagine hydrolysis remained unaffected. These findings highlight the unique and multimodal reactivity of ReAIV, suggesting its potential dual application in the food industry: in selective removal of L-asparagine and in covalent sequestration of acrylamide under mild conditions. The acrylamide modification improved crystal morphology of ReAIV, offering practical advantages for structural studies. Additionally, a covalent modification of the catalytic Ser47 residue was observed in the presented crystal structure. Based on B-factor analysis, literature data, and detection of borate contamination in the laboratory water, this modification was interpreted as an orthoborate ester.

PubMed: 42113412
DOI: 10.1007/s00726-026-03525-1

実験手法

X-RAY DIFFRACTION (1.4 Å)