메뉴 건너뛰기
.. 내서재 .. 알림
소속 기관/학교 인증
인증하면 논문, 학술자료 등을  무료로 열람할 수 있어요.
한국대학교, 누리자동차, 시립도서관 등 나의 기관을 확인해보세요
(국내 대학 90% 이상 구독 중)
로그인 회원가입 고객센터 ENG
주제분류

추천
검색

논문 기본 정보

자료유형
학위논문
저자정보

안소영 (서울대학교, 서울대학교 대학원)

지도교수
서정용
발행연도
2020
저작권
서울대학교 논문은 저작권에 의해 보호받습니다.

이용수2

표지
AI에게 요청하기
추천
검색

이 논문의 연구 히스토리 (2)

초록· 키워드

오류제보하기
Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and CRISPR associated (Cas) genes constitute a prokaryotic adaptive immune system against invading phages and plasmids. To counteract this defense mechanism, phages evolved Anti-CRISPR (Acr) proteins that can inactivate the CRISPR-Cas systems. A number of anti-CRISPR proteins have been shown to potently inhibit subgroups of CRISPR-Cas9 systems. AcrIIA1 and AcrIIA5, encoded by Listeria monocytogenes prophages and Streptococcus thermophilus, are the most prevalent among the Acr proteins targeting type II-A CRISPR-Cas systems (AcrIIA1) and potently inhibits diverse type II-A and type II-C Cas9 homologs (AcrIIA5), respectively. Here, I investigated the structural and functions of the anti-CRISPRs proteins. The AcrIIA1 structure displays its dimeric assembly with a novel two-domain architecture. AcrIIA1 exhibits structural similarity to transcriptional factors in the N-terminal domains. When overexpressed in Escherichia coli, AcrIIA1 associates with RNAs, suggesting that AcrIIA1 functions via nucleic acid recognition. AcrIIA5 reveals a novel α/β fold connected to an intrinsically disordered region (IDR). AcrIIA5 directly interacts with single-guide RNA (sgRNA)-Cas9 complex, and hinders proper association between Cas9 and sgRNA required for the nuclease activity of Cas9. Taken together, the results reveals unique structural and functional features of AcrIIA1 and AcrIIA5, suggesting its distinct mode of action and the diversity of the inhibitory mechanisms employed by Acr proteins.

목차

1. Introduction. 1
1.1. CRISPR-Cas 1
1.2. Classification of the CRISPR-Cas 2
1.3. Mechanism of the CRISPR-Cas system. 6
1.4. The discovery of Anti-CRISPR proteins. 10
1.5. Anti-CRISPRs mechanism 15
1.6. Anti-CRISPR AcrIIA1 and AcrIIA5 19
2. Materials and Methods. 21
2.1. Cloning 21
2.1.1. AcrIIA1 and AcrIIA1 L52M 21
2.1.2. AcrIA5 and AcrIIA5 mutants 21
2.2. Protein expression 22
2.2.1. Luria bertani medium 22
2.2.2. Selenomethionine labeling 22
2.2.3. Isotope labeling medium 23
2.3. Purification 26
2.3.1. AcrIIA1 and AcrIIA1 L52M. 26
2.3.2. SinR. 26
2.3.3. AcrIIA5 and AcrIIA5 mutants. 27
2.3.4. N-terminal truncation mutants of AcrIIA5 28
2.3.5. SpyCas9 28
2.4. Size exclusion chromatography 29
2.5. Crystallization, data collection and structure determination 29
2.6. Analysis of co-purifying nucleic acids 32
2.7. Isothermal Titration Calorimetry 33
2.8. NMR spectroscopy 33
2.9. Structure calculation 33
2.10. Electrophoretic mobility shift assay. 36
2.10.1. AcrIIA1 36
2.10.2. AcrIIA5 36
2.11. In vitro cleavage assay 37
2.11.1. DNA cleavage assay 37
2.11.2. RNA cleavage assay 37
2.12. sgRNA preparation. 37
3. Results (AcrIIA1) 40
3.1. Structural analysis of AcrIIA1 41
3.2. Structural feature of AcrIIA1 42
3.3. Structural similarity to HTH transcription factors. 54
3.4. AcrIIA1 interacts with RNAs 64
4. Discussion. 67
5. Conclusion 74
6. Results (AcrIIA5) 75
6.1. Resonance assignment of AcrIIA5 76
6.2. NMR Backbone assignment of AcrIIA5 76
6.3. AcrIIA5 adopts a novel fold with an IDR. 84
6.4. AcrIIA5 disrupts functional Cas-sgRNA assembly. 92
6.5. N-terminal disorder of AcrIIA5 is crucial for Cas9 inhibition 100
7. Discussion 115
8. Conclusion. 126
9. References. 127
Abstract in Korean 134

최근 본 자료

전체보기

댓글(0)

0