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Disruption of secondary structure by oxidative stress alters the cross-linking pattern of myosin by microbial

Chunqiang Li1, Youling L Xiong2

  • 1College of Food Science, Shenyang Agricultural University, Shenyang, Liaoning 110866, China; Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, Wuxi, Jiangsu 214122, China.

Meat Science
|June 13, 2015
PubMed

Insights

Oxidative stress alters porcine myofibrillar protein structure, affecting microbial transglutaminase cross-linking sites on myosin. This structural change is dependent on the level of oxidation, impacting protein functionality.

Area of Science:

  • Food Science
  • Protein Chemistry
  • Biochemistry

Background:

  • Myofibrillar proteins (MP) are crucial in meat texture and processing.
  • Oxidative stress can negatively impact protein functionality and quality.
  • Microbial transglutaminase (TGase) is used to modify protein cross-linking.

Purpose of the Study:

  • To investigate the impact of oxidative stress on porcine MP structure.
  • To determine how TGase cross-linking is affected by prior oxidation.
  • To elucidate the relationship between protein structure changes and cross-linking patterns.

Main Methods:

  • Porcine MP was subjected to oxidative stress using an iron-H2O2 system.
  • Oxidized MP was treated with microbial transglutaminase (TGase) at 4°C.
  • Changes in secondary structure were analyzed using Circular Dichroism and FTIR.
  • Myosin cross-linking sites were identified on subfragments (S1, S2, rod).

Main Results:

  • Both oxidation and TGase treatment caused helix unraveling in MP.
  • TGase-induced α-helix loss was oxidation-dependent, with mild oxidation causing the most loss.
  • Oxidation shifted TGase cross-linking sites on myosin from S1 to the rod and S2 regions.
  • Disulfide bond formation during oxidation contributed to altered cross-linking.

Conclusions:

  • Oxidative stress significantly modifies porcine MP secondary structure.
  • The level of oxidation dictates the extent of TGase-induced structural changes.
  • Oxidation-induced structural alterations redirect TGase cross-linking on myosin, impacting protein interactions.
Keywords:
Acrylamide (CID: 6579)Ascorbic acid (CID: 54670067)Cross-linkingFerric chloride (CID: 24380)Myofibrillar proteinN-ethylmaleimide (CID: 4362)Propyl gallate (CID: 4947)Protein oxidationTransglutaminaseβ-Mercaptoethanol (CID: 1567)

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