Anabaena Sensory Rhodopsin (ASR) is a microbial photosensor from the cyanobacterium Anabaena sp. PCC 7120. It was found in previous studies that ASR co-purifies with several small molecules, although their identities and structural or functional roles remained unclear. Here, we use solid-state nuclear magnetic resonance (SSNMR) spectroscopy and mass spectrometry to characterize these molecules. Numerous correlations atypical for protein amino acids were found and assigned in the SSNMR spectra. The chemical shift patterns correspond to N-acetyl-d-glucosamine, N-acetyl-d-mannosaminuronic acid, and 4-acetamido-4,6-dideoxy-d-galactose which are part of the Enterobacterial Common Antigen (ECA). These sugars undergo rapid anisotropic motions and are likely linked flexibly to a rigid anchor that tightly binds ASR. Phosphorus NMR reveals several signals that are characteristic of monophosphates, further suggesting phosphatidylglyceride as the ECA lipid carrier which is anchored to ASR. In addition, NMR signals corresponding to common phospholipid phosphatidylethanolamine (PE) have been detected. The presence of PE tightly interacting with ASR was confirmed using liquid chromatography-mass spectrometry. This article commemorates Professor Michèle Auger and her contributions to membrane biophysics and Nuclear Magnetic Resonance.

Anabaena感官视紫红质（ASR）是来自蓝细菌Anabaena sp。的微生物光传感器。PCC7120。在先前的研究中发现，ASR与几种小分子共纯化，尽管它们的身份以及结构或功能作用尚不清楚。在这里，我们使用固态核磁共振（SSNMR）光谱和质谱来表征这些分子。发现了许多非典型的蛋白质氨基酸相关性，并在SSNMR光谱中进行了分配。化学位移图案对应于Ñ乙酰基d -葡糖胺，Ñ乙酰基d -mannosaminuronic酸，和4-乙酰氨基-4,6-二脱氧d-半乳糖是肠细菌共同抗原（ECA）的一部分。这些糖会经历快速的各向异性运动，并可能灵活地与紧密结合ASR的刚性锚连接。磷NMR揭示了几个具有单磷酸特征的信号，进一步表明磷脂酰甘油酯是锚定在ASR上的ECA脂质载体。另外，已经检测到对应于普通磷脂磷脂酰乙醇胺（PE）的NMR信号。使用液相色谱-质谱法确认了PE与ASR紧密相互作用的存在。本文旨在纪念MichèleAuger教授及其对膜生物物理学和核磁共振的贡献。