The last twenty years have witnessed increasing research activity in the area of supramolecular chemistry of 1 : 1 co-assembly of melamine (M)-cyanuric acid (CA), since the historic discovery of the M$CA aggregate in crystal form and its structural analysis by Wang and his coworkers in 1990. Its useful chemical structure and fascinating H-bonding interaction sites distinguish M and its analogous derivatives as scaffolding components in the field of supramolecular chemistry to develop desired nanoto-micro scaled architecture. To date, M-based supramolecular assemblies are known in diverse forms which include fascinating nano-to micromorphological structures, molecular guest boxes, small molecular gels, membrane, sensor and liquid crystal development, polymeric scaffolds etc. In this review, we have covered the development of M and its derivatives, encompassing both nano/micro-ordered structures and advanced functional materials. Bappaditya Roy received his M.Sc. degree in Applied Chemistry from Bengal Engineering and Science University in 2008, and then he joined in Prof. Arun K. Nandi's group in 2008 at The Polymer Science Unit, Indian Association for the Cultivation of Science as a CSIR fellow. He received his Ph.D. degree in Nov. 2012, thesis entitled "Supramolecular Assembly of Melamine and its derivatives". Presently he is working as a postdoctoral fellow in Prof. Seiji Shinkai's lab at Kyushu University, Japan. His current research interests focus on host-guest chemistry and molecular recognition. Partha Bairi received his M.Sc. degree in Chemistry from Indian Institute of Technology (IIT) Madras, India in 2009. He joined Prof. Arun K. Nandi's group in July, 2009 at the Polymer Science Unit, Indian Association for the Cultivation of Science (IACS) as a CSIR fellow. His Ph.D. thesis "Studies on Photoluminescence Active Supramolecular Gels" is submitted for Ph.D. degree. His current research interests focus on energy transfer in supramolecular assembly and so materials.

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Genomic studies have indicated that certain bacterial lineages such as the Bacteroidetes lack Shine-Dalgarno (SD) sequences, and yet with few exceptions ribosomes of these organisms carry the canonical anti-SD (ASD) sequence. Here, we show that ribosomes purified from Flavobacterium johnsoniae, a representative of the Bacteroidetes, fail to recognize the SD sequence of mRNA in vitro. A cryo-electron microscopy structure of the complete 70S ribosome from F. johnsoniae at 2.8 Å resolution reveals that the ASD is sequestered by ribosomal proteins bS21, bS18 and bS6, explaining the basis of ASD inhibition. The structure also uncovers a novel ribosomal protein—bL38. Remarkably, in F. johnsoniae and many other Flavobacteriia, the gene encoding bS21 contains a strong SD, unlike virtually all other genes. A subset of Flavobacteriia have an alternative ASD, and in these organisms the fully complementary sequence lies upstream of the bS21 gene, indicative of natural covariation. In other Bacteroidetes classes, strong SDs are frequently found upstream of the genes for bS21 and/or bS18. We propose that these SDs are used as regulatory elements, enabling bS21 and bS18 to translationally control their own production.