Division of Biological Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan.
J Photochem Photobiol B. 2011 Oct 5;105(1):81-9. doi: 10.1016/j.jphotobiol.2011.07.003. Epub 2011 Jul 23.
Mycosporine-like amino acids (MAAs) are UV absorbing pigments, and structurally distinct MAAs have been identified in taxonomically diverse organisms. Two novel MAAs were purified from the cyanobacterium Nostoc commune, and their chemical structures were characterized. An MAA with an absorption maximum at 335 nm was identified as a pentose-bound porphyra-334 derivative with a molecular mass of 478 Da. Another identified MAA had double absorption maxima at 312 and 340 nm and a molecular mass of 1,050 Da. Its unique structure consisted of two distinct chromophores of 3-aminocyclohexen-1-one and 1,3-diaminocyclohexen and two pentose and hexose sugars. These MAAs had radical scavenging activity in vitro; the 1050-Da MAA contributed approximately 27% of the total radical scavenging activities in a water extract of N. commune. These results suggest that these glycosylated MAAs have multiple roles as a UV protectant and an antioxidant relevant to anhydrobiosis in N. commune.
肌肽类似氨基酸（MAAs）是具有紫外线吸收能力的色素，在分类上不同的生物中已经鉴定出结构不同的 MAAs。 从蓝细菌念珠藻中分离得到两种新型 MAAs，并对其化学结构进行了表征。在 335nm 处具有最大吸收的 MAA 被鉴定为戊糖结合的拟卟啉-334 衍生物，分子量为 478Da。另一种鉴定出的 MAA 在 312nm 和 340nm 处具有双重吸收最大值，分子量为 1050Da。其独特的结构由 3-氨基环己烯-1-酮和 1,3-二氨基环己烯以及两个戊糖和己糖组成。这些 MAAs 在体外具有清除自由基的活性；在念珠藻水提取物中，1050Da MAA 对总自由基清除活性的贡献约为 27%。这些结果表明，这些糖基化 MAAs 在念珠藻的脱水休眠中具有作为紫外线保护剂和抗氧化剂的多种作用。
