Recent advances in chemical protein synthesis:method developments and biological applications

The central dogma of modern biology underscores the pivotal roles proteins play in diverse biological processes,the study of which necessitates advanced methods to produce proteins with precision and versatility.Chemical protein synthesis,a powerful approach utilizing chemical reactions for the de novo construction of structurally accurate proteins,has emerged as a transformative tool for studying proteins and generating protein derivatives/mimics inaccessible by natural biological machinery,including post-translationally modified proteins,proteins comprised of unnatural amino acids,as well as mirror-image proteins.This review summarizes recent strides in synthetic method developments for chemical protein synthesis,including innovative techniques in solid-phase peptide synthesis,the challenges presented by difficult sequences in either synthesis or folding and the exploration of novel ligation reactions using both chemical and enzymatic methods.Furthermore,the review also delves into newly developed protocols for site-selective protein modifications and the generation of stapled or macrocyclized peptides/miniproteins,highlighting the power of chemical methods to make structurally diverse proteins.Recent applications of synthetic proteins in investigating post-translational modifications(phosphorylation,lipidation,glycosylation,ubiquitination,etc.),mirror-image biological processes and drug development are further discussed.Together,these topics provide a comprehensive overview of the current landscape of chemical protein synthesis.

Distributed Fiber Birefringence Measurement Using Pulse-CompressionФ-OTDR

In this paper,a novel birefringence measurement method through the Rayleigh backscattered lightwave within single-mode fiber is proposed,using a single chirped-pulse with arbitrary state of polarization.Numerical analysis is carried out in detail,then pulse-compression phase-sensitive optical time domain reflectometry(PC-O-OTDR)with polarization-diverse coherent detection is employed to verify this method.A 2 km spun single-mode fiber is tested with 8.6cm spatial resolution,and the average birefringence of the fiber under test is measured as 0.234rad/m,which is consistent with previous literatures about single-mode fiber.Moreover,the relationship between the measured birefringence and the spatial resolution is also studied for the first time,and the results show that spatial resolution is crucial for fiber birefringence measurement.

Synthesis of Ras proteins and their application in biofunctional studies

Approximately 30% of human cancers are associated with RAS mutation. Ras proteins on the plasma membrane regulate a plenty of important cellular processes. The post-translational modifications(PTMs)of Ras proteins like lipidation and methylation are crucial for their correct cellular localization and biological function. Hence, obtaining Ras proteins with different kinds of modifications is the necessary prerequisite to investigate their biological properties at molecular level. In this review, we mainly summarize the developed strategies including chemical total synthesis, biosynthesis and semi-synthesis for producing Ras proteins with modifications and their application in biological studies.

Quantitative Measurement of γ-Ray and e-Beam Effects on Fiber Rayleigh Scattering Coefficient

The effects of gamma ray(γ-ray)radiation and electron beam(e-beam)radiation on Rayleigh scattering coefficient in single-mode fiber are experimentally investigated.Utilizing an optical time domain reflectometry(OTDR),the power distribution curves of the irradiated fibers are obtained to retrieve the corresponding radiation-induced attenuation(RIA).Based on the backscattering power levels and the measured RIAs,the Rayleigh scattering coefficients can be characterized quantitatively for each fiber sample.Under the given radiation conditions,Rayleigh scattering coefficients have been changed very little while RIAs have been changed significantly.Furthermore,simulations have been implemented to verify the validity of the measured Rayleigh scattering coefficient,including the splicing points.

Erratum to: Distributed Fiber Birefringence Measurement Using Pulse-Compression Ф-OTDR

Erratum to:Distributed Fiber Birefringence Measurement Using Pulse-Compression Ф-OTDR The original article unfortunately contained a mistake.Figures 4 and 8 are not clear.The figures in original article and in corrected article are as follows.