As one of the most important and influential peptide conferences in the world, Chinese International Peptide Symposium (CPS) was founded in 1990 and has been held every two years for 14 consecutive sessions. From July 4^th to 6^th, 2018, the 15^th CPS will be held in Shenzhen and hosted by Tsinghua University. This conference will focus on the topics of “Peptide: Technological Innovation and a Better Life”, covering the synthesis, structure and function of peptides and proteins, peptide-based drug discovery, peptide materials, proteomics and metabolomics, immunotherapy and other frontiers. The purpose of this special issue of Chinese Chemical Letters is to celebrate this meeting and share with the readers the latest and most cutting-edge research in the field of peptide chemistry, peptide biology, peptide pharmacy, and peptide material science.

There are totally 16 original research papers and 17 reviews in this special issue. In the area of methods for peptide synthesis, Xu et al. reported the development of chemoselective aspartic acid ligation [1]. Zhou et al. developed an on-resin peptide ligation via C-terminal benzyl ester [2]. Du et al. used peptide selenoesters in glycopeptide ligation [3]. Liu et al. [4] developed a facile synthesis of β-hydroxy aspartic acid and its derivatives. Lu et al. [5] reviewed the use transition metal-catalyzed C-H functionalization methods for late-stage modification of peptides. Zhu et al. [6] developed an enzyme for the C-terminal click-functionalization of peptides. Lin et al. [7] reviewed the enzymes used for synthesis and modification of peptides. Xu et al. [8] surveyed advances in enzyme-mediated peptide ligation. Liu et al. [9] report their synthetic studies towards human interleukin-5.

In the field of naturally occurring bioactive peptides, Chen et al. [10] described the synthesis of guanylate cyclase C agonist linacoltide and its D-enantiomer for racemic crystallization. Guo et al. [11] reported the total synthesis of snake toxin α-bungarotoxin and its analogues. Yin et al. [12] reviewed the distribution of micropeptide-coding small open reading frames (sORFs) in transcripts. Tang et al. [13] reviewed the discovery and biosynthesis of thioviridamide-like compounds. Fang et al. [14] reviewed the discovery, structure and chemical synthesis of disulfide-rich peptide toxins. Luo et al. [15] reported the synthesis of proline-rich cyclic peptide, reniochalistatin E and its conformational isomers.

Regarding peptides in biochemical studies, Hu et al. [16] reviewed synthesis and functional studies of Ras proteins with various post-translational modifications. Liang et al. [17] examined the biochemical properties of synthetic branched ubiqutitins. Lin et al. [18] reviewed peptide-based tools to identify and characterize proteins that recognize histone post-translational modifications. Feng reported a proximity-induced covalent fluorescent probe for selective detection of bromodomain [19]. So et al. [20] provided a brief account of peptide photocaging as a useful technology. Chen et al. [21] explored the underlying interaction mechanism of RAGE TM domains by multiscale coarse-grained dynamic simulation.

For the applications of peptides in biomedicine, Kai et al. [22] studied the effects of different linker amino acids on the bioactivities of hereomeric antimicrobial peptides. Liu and Wu [23] provided a mini-review with perspectives on multicyclic peptide mimics of antibodies. Guo et al. [24] found that stapled SC34EK fusion inhibitors exhibited improved anti-HIV-1 activities. Qin et al. [25] reported a potent peptide inhibitor of estrogen receptor α using N-terminus helix-nucleating strategy. Jiang et al. [26] surveyed the macrocyclic peptides as regulators of proteinprotein interactions. Li et al. [27] provided the general methods for engineering therapeutic peptides. Zhao et al. [28] reviewed the sulfur-containing peptides in drug discovery. Li et al. [29] summarized the peptide stapling strategies to stabilize the alpha-helical peptides. Xu et al. [30] reviewed peptide-based probes for multifunctional biomedical imaging. Chen et al. [31] developed improved EGFR targeting peptide-conjugated phthalocyanine photosensitizers for tumor photodynamic therapy. Wu et al. [32] summarized the development of the photosensitive supramolecular peptide hydrogels over the recent decades. Finally, Wu et al. [33] reviewed the programmable pyrrole-imidazole polyamides.

We wish that this special issue would provide the readers an overview of the versatile research subjects in peptide science. We anticipate that the rapid development of peptide science would greatly enhance our understanding of this family of fascinating molecules and expand our horizon of making better use of peptides to solve the problems in biomedicine and advanced materials.