The molecular mechanism of yeast histone partner Chz1 specific identification of H2A.Z was revealed.

In eukaryotic cells, histone variants are assembled to form special chromatin structures, which are different from conventional histones, which is one of the important ways of epigenetic regulation.
histone variant H2A.Z has a similar primary sequence to conventional histone H2A, H2A. Z is the necessary gene of multicellular organisms and plays a vital role in gene transcription regulation, DNA damage repair, cell proliferation, differentiation, etc.
In recent years, the Zhou Zheng Research Group of the Institute of Biophysics of the Chinese Academy of Sciences has conducted a systematic study of the specific identification of histone variants using structural biology and biochemistry, and has reported on the structure and molecular mechanism of Anp32e's identification of H2A.Z and its removal of chromatin (Cell Research 2014), as well as the structure and molecular mechanisms of chromatylyl1 identification of Chromaels and its chromatin assembly .26. On May 31,
, the Zhou Political Research Group published online in the journal PLOS Biology, entitled Restructuring insights into histone chaperone Chz1-mediated H2A. The research paper z and histone replace revealed the structure and molecular mechanisms of the yeast histone companion Chz1 specifically identified histone variant H2A.Z and its promoter SWR1 catalytic H2A.Z replacement.
Chz1 was one of the first protein molecules to be identified specifically identifiable to identify histone variant H2A.Z, and was also a unique H2A.Z histone companion for yeast cells.
Chz1 binds to free H2A.Z-H2B dipolymers in yeast cells and promotes H2A.Z exchange reactions catalyzed by chromatin remodeling complex SRCAP/SWR. How does
Chz1 specifically identify H2A.Z? How to promote the H2A.Z exchange reaction of SRCAP/SWR catalyzed by combining the free H2A.Z-H2B dipolymer? These key scientific questions have yet to be answered.
the study first determined the crystal structure of the C-end of Chz1 and the compound formed by the H2A.Z-H2B dipolymer, and ITC experiments showed that the specificity of the identification of H2A.Z by the full length Chz1 (Chz1-FL) was greatly improved compared with the previously reported Chz1-M.
second, the study found the importance of two highly conservative amino acid residues (Gly98 and Ala57) in H2A.Z for Chz1 specific identification, thus revealing a new H2A.Z specific identification mechanism (Figure 1), which was the first site for protein-specific identification in the N-end region of H2A.Z.
finally, SWR1 enzyme activity theastodetermined found that the free H2A.Z-H2B dipolymer inhibited the H2A.Z switching of SWR1, which was removed by binding the free H2A.Z-H2B, thus facilitating the exchange reaction of H2A.Z (Figure 2).
the study sheds light on the molecular mechanism of histone partner Chz1-specific identification of H2A.Z, a new recognition pattern that is different from all reported H2A.Z identification patterns, expanding the understanding of H2A.Z's specific recognition mechanism.
the study also revealed how Chz1 promotes H2A.Z switching by controlling the concentration of free H2A.Z-H2B dipolymer, and the findings provide the basis for further study of H2A.Z (Figure 2). Wang Yunyun, a doctoral student at
Zhou Zheng's research group, is the first author of the paper, and Zhou Zheng is the communication author of the paper.
the work is supported by the Fund Committee, the Ministry of Science and Technology, the Chinese Academy of Sciences Class B pilot special funding support.
Johns Hopkins University professor Carl Wu and Ed Luk, a professor at the State University of New York at Stony Brook, contributed to this effort.
study revealed the specific identification and catalytic mechanism of the brewery yeast histone demethylator Rph1 substrate, on November 10, 2010, The research results of the Biochemical and Cell Institute of the Shanghai Institute of Life Sciences of the Chinese Academy of Sciences on the specific identification and catalytic mechanism of the brewery yeast histone demethylator Rph1 substrate.
a family of proteins containing the JmjC domain in eukaryotes such as humans and yeasts, and studies have shown that many of their members have histone demethylase activity and use Fe2 plus and alpha-ketone diacid as co-factors.
human source JMJD2A can be specific to demethylating H3K36me3/2 and H3K9me3/2.
Rph1 is a homologous in winey yeast, which can be specific to demethylating H3K36me3/2, which plays an important role in the transcription extension of certain transcription-activated genes.
Ding Jianping group of doctoral students Chang Wei and others analyzed the structure of the Rph1 catalytic core region, as well as the structure of the Ni2 plus and alpha-ketone diacid complex.
, Ni2 plus is used to simulate the binding form of Fe2 plus.
the catalytic core region of Rph1 has the same histone demethylase activity and substrate specificity as the full-length protein.
these structures reveal that the Rph1 catalytic core area consists of the JmjN domain, the long b-card structure, the mixed domain formed by the a-helix and ring area, and the JmjC domain.
at the catalytic core, Ni2 plus stabilizes its binding by forming a ligand bonds with three conservative amino acids (His235, Glu237 and His323) and a-ketone diacid, while a-ketone diacid forms a hydro-bonding action with the side chain of three conservative amino acids (Tyr183, Asn245 and Lys253).
Based on the structure of the Rph1 core region and the structure of the JMJD2A core region combined with the H3K36me3 peptide segment complex, the researchers hypothesized that the substrate binding site of Rph1 was located on the surface of the core area, mainly by the long b-card structure, a The hybrid domain formed by the helix and ring regions, as well as the structure of the conservative JmjC domain, and the methylated H3K36 can be extended into the pockets formed by the JmjC domain and stabilized by acting with the hydrogen bonds of several conservative amino acids.
based on these analyses and comparisons, binding point mutations, in vitro histone demethylase activation tests and yeast phenotypic screening experiments, they found that after the mutation sin-binding point of amino acids with Ni2, a-ketone diacid and peptide segments, Rph1 lost enzyme activity, but also lost the function of promoting transcriptional extension in the yeast body, resulting in yeast growth defects.
the above results reveal the specific identification and catalysis mechanism of histone demethylase Rph1 substrate in winey yeast.
the work is supported by funds from the Ministry of Science and Technology, the National Natural Science Foundation of China, the Chinese Academy of Sciences and the Shanghai Science and Technology Commission.
Source: Institute of Biophysics.