为探究表没食子儿茶素没食子酸酯-牛骨蛋白(Epigallocatechin-3-gallate-Bovine bone protein,EGCG-BBP)对乳化肉制品蛋白结构及贮藏氧化稳定性的影响,本文研究不同EGCG-BBP添加量对生肉糜中肌原纤维蛋白(Myofibrillar protein,MP)的理...为探究表没食子儿茶素没食子酸酯-牛骨蛋白(Epigallocatechin-3-gallate-Bovine bone protein,EGCG-BBP)对乳化肉制品蛋白结构及贮藏氧化稳定性的影响,本文研究不同EGCG-BBP添加量对生肉糜中肌原纤维蛋白(Myofibrillar protein,MP)的理化性质、结构特性以及对肉丸氧化特性的影响。结果表明:当EGCG-BBP添加量为0.8%时,肉糜中MP的巯基含量最高,达4.06 nmol/mg蛋白,且羰基含量及表面疏水性最低,能够有效提升乳化肉制品的抗氧化能力。由红外光谱分析表明,与未添加EGCG-BBP组相比,添加共价物肉糜中MP的酰胺A带峰值所对应的波数明显增大,说明MP的二级结构会随之发生改变;荧光光谱显示,随贮藏时间延长,对照组中MP的最强荧光波长发生显著红移,但随EGCG-BBP浓度的增加,红移程度显著降低,表明添加EGCGBBP能够改变MP的三级结构。此外,乳化肉丸贮藏过程中的氧化指标分析表明,添加0.8%EGCG-BBP能显著降低肉丸的过氧化值(PV)和硫代巴比妥酸值(TBARs),从而提高其氧化稳定性。综上所述,EGCG-BBP能够显著改变MP的二、三级结构,且具有良好的抗氧化性能,在提升乳化肉制品品质方面具有很大的应用潜力,为肉品抗氧化型乳化剂的应用提供新的选择。展开更多
目的验证在大鼠节段性骨缺损模型中骨形态发生蛋白结合肽（BMP Binding Peptide,BBP）对于重组人骨形态发生蛋白-2（recombinent human bone morphogenetic protein-2,rhBMP-2）骨诱导作用的影响。方法 70只缺损大鼠分别分成7组,每组不...目的验证在大鼠节段性骨缺损模型中骨形态发生蛋白结合肽（BMP Binding Peptide,BBP）对于重组人骨形态发生蛋白-2（recombinent human bone morphogenetic protein-2,rhBMP-2）骨诱导作用的影响。方法 70只缺损大鼠分别分成7组,每组不同剂量的rhBMP-2＋/-1000 gBBP,4w和8w后分别摄片,动物8w后处死,股骨样本分别手工评估,采用uCT测量骨容积,随后分别采用组织学和生物力学分析。结果高剂量（10 g）rhBMP-2组术后8w可见骨愈合,骨缺损处骨完全覆盖和桥接,但低剂量（5 g和2 g）rhBMP-2组术后8w骨愈合欠佳。与单独应用rhBMP-2相比,使用低剂量的rhBMP-2复合一定量的BBP可以取得更满意的骨形成量。BBP增强rhBMP-2的骨形成活性发生于4~8w时,而在术后早期并无明显作用。单纯应用BBP仅可见骨缺损处局部的钙化,未见骨愈合。结论 BBP能显著增强rhBMP-2的骨形成活性,这种增强作用需要一定时间来产生效果;其活性发生于术后4~8w时,在术后早期并无明显作用。而且BBP本身并没有骨诱导潜力,仅仅能增强rhBMP-2的骨形成活性。BBP起到缓释作用,与rhBMP-2紧密结合后,让rhBMP-2缓慢而持久的释放。展开更多
Bone sialoprotein-binding protein （Bbp）, a MSCRAMMs （Microbial Surface Components Recognizing Adhesive Matrix Molecules） family protein expressed on the surface of Staphylococcus aureus （S. aureus）, mediates adh...Bone sialoprotein-binding protein （Bbp）, a MSCRAMMs （Microbial Surface Components Recognizing Adhesive Matrix Molecules） family protein expressed on the surface of Staphylococcus aureus （S. aureus）, mediates adherence to fibrinogen a （Fg a）, a component in the extracellular matrix of the host cell and is important for infection and pathogenesis. In this study, we solved the crystal structures of apo-Bbp273-598 and Bbp273-598-Fg a561-575 complex at a resolution of 2.03 A and 1.45 A, respectively. Apo-Bbp273-598 contained the ligand binding region N2 and N3 domains, both of which followed a DE variant IgG fold characterized by an additional DI strand in N2 domain and D1＇ and D2＇ strands in N3 domain. The peptide mapped to the Fg o561-575 bond to Bbp273-sgs on the open groove between the N2 and N3 domains. Strikingly, the disordered C-terminus in the apo-form reorganized into a highly-ordered loop and a β-strand G＂ covering the ligand upon ligand binding. BbpAla298-Gly301 in the N2 domain of the Bbp273-598-Fg a561-575 complex, which is a loop in the apo-form, formed a short a-helix to interact tightly with the peptide. In addition, Bbpser547-Glns61 in the N3 domain moved toward the binding groove to make contact directly with the peptide, while BbpAsp338-Gly355 and BbpThr365-Tyr387 in N2 domain shifted their configurations to stabilize the reorganized C-terminus mainly through strong hydrogen bonds. Altogether, our results revealed the molecular basis for Bbp-ligand interaction and advanced our understanding of S. aureus infection process.展开更多
文摘为探究表没食子儿茶素没食子酸酯-牛骨蛋白(Epigallocatechin-3-gallate-Bovine bone protein,EGCG-BBP)对乳化肉制品蛋白结构及贮藏氧化稳定性的影响,本文研究不同EGCG-BBP添加量对生肉糜中肌原纤维蛋白(Myofibrillar protein,MP)的理化性质、结构特性以及对肉丸氧化特性的影响。结果表明:当EGCG-BBP添加量为0.8%时,肉糜中MP的巯基含量最高,达4.06 nmol/mg蛋白,且羰基含量及表面疏水性最低,能够有效提升乳化肉制品的抗氧化能力。由红外光谱分析表明,与未添加EGCG-BBP组相比,添加共价物肉糜中MP的酰胺A带峰值所对应的波数明显增大,说明MP的二级结构会随之发生改变;荧光光谱显示,随贮藏时间延长,对照组中MP的最强荧光波长发生显著红移,但随EGCG-BBP浓度的增加,红移程度显著降低,表明添加EGCGBBP能够改变MP的三级结构。此外,乳化肉丸贮藏过程中的氧化指标分析表明,添加0.8%EGCG-BBP能显著降低肉丸的过氧化值(PV)和硫代巴比妥酸值(TBARs),从而提高其氧化稳定性。综上所述,EGCG-BBP能够显著改变MP的二、三级结构,且具有良好的抗氧化性能,在提升乳化肉制品品质方面具有很大的应用潜力,为肉品抗氧化型乳化剂的应用提供新的选择。
文摘Bone sialoprotein-binding protein （Bbp）, a MSCRAMMs （Microbial Surface Components Recognizing Adhesive Matrix Molecules） family protein expressed on the surface of Staphylococcus aureus （S. aureus）, mediates adherence to fibrinogen a （Fg a）, a component in the extracellular matrix of the host cell and is important for infection and pathogenesis. In this study, we solved the crystal structures of apo-Bbp273-598 and Bbp273-598-Fg a561-575 complex at a resolution of 2.03 A and 1.45 A, respectively. Apo-Bbp273-598 contained the ligand binding region N2 and N3 domains, both of which followed a DE variant IgG fold characterized by an additional DI strand in N2 domain and D1＇ and D2＇ strands in N3 domain. The peptide mapped to the Fg o561-575 bond to Bbp273-sgs on the open groove between the N2 and N3 domains. Strikingly, the disordered C-terminus in the apo-form reorganized into a highly-ordered loop and a β-strand G＂ covering the ligand upon ligand binding. BbpAla298-Gly301 in the N2 domain of the Bbp273-598-Fg a561-575 complex, which is a loop in the apo-form, formed a short a-helix to interact tightly with the peptide. In addition, Bbpser547-Glns61 in the N3 domain moved toward the binding groove to make contact directly with the peptide, while BbpAsp338-Gly355 and BbpThr365-Tyr387 in N2 domain shifted their configurations to stabilize the reorganized C-terminus mainly through strong hydrogen bonds. Altogether, our results revealed the molecular basis for Bbp-ligand interaction and advanced our understanding of S. aureus infection process.
