Delcourte Loic, Berbon Mélanie, Rodriguez Marion, Delhaes Laurence, Habenstein Birgit, Loquet Antoine
Univ Bordeaux, CNRS, Bordeaux INP, CBMN, UMR 5248, IECB, Pessac, France.
CNR des Aspergilloses Chroniques, Mycology-Parasitology Department, CHU Bordeaux, 33000, Bordeaux, France.
Solid State Nucl Magn Reson. 2025 Mar 14;137:102002. doi: 10.1016/j.ssnmr.2025.102002.
Chitin is the most important nitrogen-containing polysaccharide found on Earth. This polysaccharide is a polymer of an N-acetylglucosamine and it is a crucial structural component of fungal cell walls and crustaceans. Magic-angle spinning solid-state NMR is emerging as a powerful analytical approach to study polysaccharides in the context of intact cell walls and whole cells. The presence of an acetamido group in chitin is attractive for N solid-state NMR. Here we investigate the use of various multi-step polarization transfer experiments incorporating indirect N detection at moderate spinning frequency, adapted from pulse sequences commonly employed for residue resonance assignment in biosolid proteins. The C,N chitin spin topology slightly differs from amino acids, and we discussed the use of frequency-selective N-C cross-polarization transfers followed by broadband or frequency-selective homonuclear C-C transfers to detect chitin resonances. Demonstrated here for chitin found in the cell wall of the fungus Aspergillus fumigatus, the use of indirect N detection through multi-step polarization transfers could be advantageous to investigate more complex nitrogen-containing polysaccharides found in whole cells and peptidoglycan samples.
几丁质是地球上发现的最重要的含氮多糖。这种多糖是N - 乙酰葡糖胺的聚合物，是真菌细胞壁和甲壳类动物的关键结构成分。魔角旋转固态核磁共振正成为一种强大的分析方法，用于在完整细胞壁和全细胞的背景下研究多糖。几丁质中乙酰氨基的存在对氮固态核磁共振很有吸引力。在这里，我们研究了各种多步极化转移实验的应用，这些实验在中等旋转频率下结合了间接氮检测，改编自常用于生物固体蛋白质中残基共振归属的脉冲序列。几丁质的C,N自旋拓扑结构与氨基酸略有不同，我们讨论了使用频率选择性N - C交叉极化转移，随后进行宽带或频率选择性同核C - C转移来检测几丁质共振。通过多步极化转移进行间接氮检测的方法，已在烟曲霉细胞壁中的几丁质上得到证明，该方法可能有利于研究全细胞和肽聚糖样品中更复杂的含氮多糖。
