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Tang S, Cai J, Zhou K, Mei Z, Huang D, Liu L, Yang L, Yin D, Hu L. Cu-MOFs@AuPtNPs nanozyme-based immunosorbent assay for colorimetric detection of alpha-fetoprotein. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2024. [PMID: 39225244 DOI: 10.1039/d4ay01410c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Accurate detection of tumor biomarkers in blood is crucial for diagnosing and treating tumor disease. In this study, a metal enzyme-linked immunosorbent assay (MeLISA) was fabricated for the ultrasensitive and naked-eye detection of tumor biomarker alpha-fetoprotein (AFP) in clinical serum samples. Herein, novel copper metal-organic frameworks and gold platinum nanoparticle composites (Cu-MOFs@AuPtNPs) were synthesized for the first time by an in situ method, which showed an enormous specific surface area and excellent peroxidase (POx) mimicking properties. Cu-MOFs@AuPtNPs linked with antibodies targeting AFP served as a signal nanoprobe to amplify the detection signal. Additionally, the specificity of MeLISA was significantly enhanced through a conventional antigen-antibody reaction and efficient blocking of non-specific sites with BSA. Under optimal conditions, the sandwich-type MeLISA exhibited a wide range from 0.001 to 1000 ng mL-1 (R2 = 0.997) and a low detection limit of 0.86 pg mL-1 (S/N = 3) with acceptable stability, selectivity, and reproducibility. It is noteworthy that the suggested MeLISA performed exceptionally well in detecting clinical serum samples, which were visible to the naked eye and did not require complex platforms. To sum up, the innovative MeLISA based on Cu-MOFs@AuPtNPs provides an alternative method for early cancer diagnosis, particularly in economically backward areas where simple diagnostic apparatus is extremely desirable.
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Affiliation(s)
- Sitian Tang
- Department of Clinical Laboratory Medicine, The People's Hospital of Chongqing Liangjiang New Area, No. 199 Ren Xing Road, Yubei, Chongqing, 401121, PR China.
| | - Juan Cai
- Department of Clinical Laboratory Medicine, Southwest Hospital, Army Medical University, Chongqing, 400038, PR China
| | - Kai Zhou
- Department of Spine Surgery, The People's Hospital of Chongqing Liangjiang New Area, No. 199 Ren Xing Road, Yubei, Chongqing, 401121, PR China
| | - Zhu Mei
- Department of Clinical Laboratory Medicine, The People's Hospital of Chongqing Liangjiang New Area, No. 199 Ren Xing Road, Yubei, Chongqing, 401121, PR China.
| | - Dongmei Huang
- Department of Clinical Laboratory Medicine, The People's Hospital of Chongqing Liangjiang New Area, No. 199 Ren Xing Road, Yubei, Chongqing, 401121, PR China.
| | - Ling Liu
- Department of Clinical Laboratory Medicine, The People's Hospital of Chongqing Liangjiang New Area, No. 199 Ren Xing Road, Yubei, Chongqing, 401121, PR China.
| | - Lunyu Yang
- Department of Clinical Laboratory Medicine, The People's Hospital of Chongqing Liangjiang New Area, No. 199 Ren Xing Road, Yubei, Chongqing, 401121, PR China.
| | - Dan Yin
- Department of Clinical Laboratory Medicine, The People's Hospital of Chongqing Liangjiang New Area, No. 199 Ren Xing Road, Yubei, Chongqing, 401121, PR China.
| | - Liyi Hu
- Department of Clinical Laboratory Medicine, The People's Hospital of Chongqing Liangjiang New Area, No. 199 Ren Xing Road, Yubei, Chongqing, 401121, PR China.
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Delzell S, Nelson SW, Frost MP, Klingbeil MM. Trypanosoma brucei Mitochondrial DNA Polymerase POLIB Contains a Novel Polymerase Domain Insertion That Confers Dominant Exonuclease Activity. Biochemistry 2022; 61:2751-2765. [PMID: 36399653 PMCID: PMC9731263 DOI: 10.1021/acs.biochem.2c00392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 10/31/2022] [Indexed: 11/19/2022]
Abstract
Trypanosoma brucei and related parasites contain an unusual catenated mitochondrial genome known as kinetoplast DNA (kDNA) composed of maxicircles and minicircles. The kDNA structure and replication mechanism are divergent and essential for parasite survival. POLIB is one of three Family A DNA polymerases independently essential to maintain the kDNA network. However, the division of labor among the paralogs, particularly which might be a replicative, proofreading enzyme, remains enigmatic. De novo modeling of POLIB suggested a structure that is divergent from all other Family A polymerases, in which the thumb subdomain contains a 369 amino acid insertion with homology to DEDDh DnaQ family 3'-5' exonucleases. Here we demonstrate recombinant POLIB 3'-5' exonuclease prefers DNA vs RNA substrates and degrades single- and double-stranded DNA nonprocessively. Exonuclease activity prevails over polymerase activity on DNA substrates at pH 8.0, while DNA primer extension is favored at pH 6.0. Mutations that ablate POLIB polymerase activity slow the exonuclease rate suggesting crosstalk between the domains. We show that POLIB extends an RNA primer more efficiently than a DNA primer in the presence of dNTPs but does not incorporate rNTPs efficiently using either primer. Immunoprecipitation of Pol I-like paralogs from T. brucei corroborates the pH selectivity and RNA primer preferences of POLIB and revealed that the other paralogs efficiently extend a DNA primer. The enzymatic properties of POLIB suggest this paralog is not a replicative kDNA polymerase, and the noncanonical polymerase domain provides another example of exquisite diversity among DNA polymerases for specialized function.
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Affiliation(s)
- Stephanie
B. Delzell
- Department
of Microbiology, University of Massachusetts, Amherst, Massachusetts01003, United States
| | - Scott W. Nelson
- Roy
J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa50011, United States
| | - Matthew P. Frost
- Department
of Microbiology, University of Massachusetts, Amherst, Massachusetts01003, United States
| | - Michele M. Klingbeil
- Department
of Microbiology, University of Massachusetts, Amherst, Massachusetts01003, United States
- The
Institute for Applied Life Sciences, University
of Massachusetts, Amherst, Massachusetts01003, United States
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Balint E, Unk I. Manganese Is a Strong Specific Activator of the RNA Synthetic Activity of Human Polη. Int J Mol Sci 2021; 23:ijms23010230. [PMID: 35008656 PMCID: PMC8745064 DOI: 10.3390/ijms23010230] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 12/21/2021] [Accepted: 12/23/2021] [Indexed: 12/02/2022] Open
Abstract
DNA polymerase η (Polη) is a translesion synthesis polymerase that can bypass different DNA lesions with varying efficiency and fidelity. Its most well-known function is the error-free bypass of ultraviolet light-induced cyclobutane pyrimidine dimers. The lack of this unique ability in humans leads to the development of a cancer-predisposing disease, the variant form of xeroderma pigmentosum. Human Polη can insert rNTPs during DNA synthesis, though with much lower efficiency than dNTPs, and it can even extend an RNA chain with ribonucleotides. We have previously shown that Mn2+ is a specific activator of the RNA synthetic activity of yeast Polη that increases the efficiency of the reaction by several thousand-fold over Mg2+. In this study, our goal was to investigate the metal cofactor dependence of RNA synthesis by human Polη. We found that out of the investigated metal cations, only Mn2+ supported robust RNA synthesis. Steady state kinetic analysis showed that Mn2+ activated the reaction a thousand-fold compared to Mg2+, even during DNA damage bypass opposite 8-oxoG and TT dimer. Our results revealed a two order of magnitude higher affinity of human Polη towards ribonucleotides in the presence of Mn2+ compared to Mg2+. It is noteworthy that activation occurred without lowering the base selectivity of the enzyme on undamaged templates, whereas the fidelity decreased across a TT dimer. In summary, our data strongly suggest that, like with its yeast homolog, Mn2+ is the proper metal cofactor of hPolη during RNA chain extension, and selective metal cofactor utilization contributes to switching between its DNA and RNA synthetic activities.
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