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Ropo M, Blum V, Baldauf C. Trends for isolated amino acids and dipeptides: Conformation, divalent ion binding, and remarkable similarity of binding to calcium and lead. Sci Rep 2016; 6:35772. [PMID: 27808109 PMCID: PMC5093913 DOI: 10.1038/srep35772] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 10/03/2016] [Indexed: 12/16/2022] Open
Abstract
We derive structural and binding energy trends for twenty amino acids, their dipeptides, and their interactions with the divalent cations Ca2+, Ba2+, Sr2+, Cd2+, Pb2+, and Hg2+. The underlying data set consists of more than 45,000 first-principles predicted conformers with relative energies up to ~4 eV (~400 kJ/mol). We show that only very few distinct backbone structures of isolated amino acids and their dipeptides emerge as lowest-energy conformers. The isolated amino acids predominantly adopt structures that involve an acidic proton shared between the carboxy and amino function. Dipeptides adopt one of two intramolecular-hydrogen bonded conformations C5 or . Upon complexation with a divalent cation, the accessible conformational space shrinks and intramolecular hydrogen bonding is prevented due to strong electrostatic interaction of backbone and side chain functional groups with cations. Clear correlations emerge from the binding energies of the six divalent ions with amino acids and dipeptides. Cd2+ and Hg2+ show the largest binding energies-a potential correlation with their known high acute toxicities. Ca2+ and Pb2+ reveal almost identical binding energies across the entire series of amino acids and dipeptides. This observation validates past indications that ion-mimicry of calcium and lead should play an important role in a toxicological context.
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Affiliation(s)
- M. Ropo
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
- Department of Physics, Tampere University of Technology, Finland
- COMP, Department of Applied Physics, Aalto University, Finland
| | - V. Blum
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC, USA
| | - C. Baldauf
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
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Denduluri SK, Idowu O, Wang Z, Liao Z, Yan Z, Mohammed MK, Ye J, Wei Q, Wang J, Zhao L, Luu HH. Insulin-like growth factor (IGF) signaling in tumorigenesis and the development of cancer drug resistance. Genes Dis 2015; 2:13-25. [PMID: 25984556 PMCID: PMC4431759 DOI: 10.1016/j.gendis.2014.10.004] [Citation(s) in RCA: 220] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 10/15/2014] [Indexed: 12/18/2022] Open
Abstract
One of the greatest obstacles to current cancer treatment efforts is the development of drug resistance by tumors. Despite recent advances in diagnostic practices and surgical interventions, many neoplasms demonstrate poor response to adjuvant or neoadjuvant radiation and chemotherapy. As a result, the prognosis for many patients afflicted with these aggressive cancers remains bleak. The insulin-like growth factor (IGF) signaling axis has been shown to play critical role in the development and progression of various tumors. Many basic science and translational studies have shown that IGF pathway modulators can have promising effects when used to treat various malignancies. There also exists a substantial body of recent evidence implicating IGF signaling dysregulation in the dwindling response of tumors to current standard-of-care therapy. By better understanding both the IGF-dependent and -independent mechanisms by which pathway members can influence drug sensitivity, we can eventually aim to use modulators of IGF signaling to augment the effects of current therapy. This review summarizes and synthesizes numerous recent investigations looking at the role of the IGF pathway in drug resistance. We offer a brief overview of IGF signaling and its general role in neoplasia, and then delve into detail about the many types of human cancer that have been shown to have IGF pathway involvement in resistance and/or sensitization to therapy. Ultimately, our hope is that such a compilation of evidence will compel investigators to carry out much needed studies looking at combination treatment with IGF signaling modulators to overcome current therapy resistance.
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Affiliation(s)
- Sahitya K. Denduluri
- The University of Chicago Pritzker School of Medicine, Chicago, IL 60637, USA
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, 5841 South Maryland Avenue, MC 3079, Chicago, IL 60637, USA
| | - Olumuyiwa Idowu
- The University of Chicago Pritzker School of Medicine, Chicago, IL 60637, USA
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, 5841 South Maryland Avenue, MC 3079, Chicago, IL 60637, USA
| | - Zhongliang Wang
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, 5841 South Maryland Avenue, MC 3079, Chicago, IL 60637, USA
- Ministry of Education Key Laboratory of Diagnostic Medicine, The Affiliated Hospitals of Chongqing Medical University, Chongqing 400016, China
| | - Zhan Liao
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, 5841 South Maryland Avenue, MC 3079, Chicago, IL 60637, USA
- Department of Orthopaedic Surgery, Xiang-Ya Hospital of Central South University, Changsha 410008, China
| | - Zhengjian Yan
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, 5841 South Maryland Avenue, MC 3079, Chicago, IL 60637, USA
- Ministry of Education Key Laboratory of Diagnostic Medicine, The Affiliated Hospitals of Chongqing Medical University, Chongqing 400016, China
| | - Maryam K. Mohammed
- The University of Chicago Pritzker School of Medicine, Chicago, IL 60637, USA
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, 5841 South Maryland Avenue, MC 3079, Chicago, IL 60637, USA
| | - Jixing Ye
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, 5841 South Maryland Avenue, MC 3079, Chicago, IL 60637, USA
- School of Bioengineering, Chongqing University, Chongqing, China
| | - Qiang Wei
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, 5841 South Maryland Avenue, MC 3079, Chicago, IL 60637, USA
- Ministry of Education Key Laboratory of Diagnostic Medicine, The Affiliated Hospitals of Chongqing Medical University, Chongqing 400016, China
| | - Jing Wang
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, 5841 South Maryland Avenue, MC 3079, Chicago, IL 60637, USA
- Ministry of Education Key Laboratory of Diagnostic Medicine, The Affiliated Hospitals of Chongqing Medical University, Chongqing 400016, China
| | - Lianggong Zhao
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, 5841 South Maryland Avenue, MC 3079, Chicago, IL 60637, USA
- Department of Orthopaedic Surgery, the Second Affiliated Hospital of Lanzhou University, Lanzhou, Gansu 730000, China
| | - Hue H. Luu
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, 5841 South Maryland Avenue, MC 3079, Chicago, IL 60637, USA
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Inhibitory mechanism of dimercaptopropanesulfonic acid (DMPS) in the cellular biomethylation of arsenic. Biochimie 2014; 106:167-74. [PMID: 25194983 DOI: 10.1016/j.biochi.2014.08.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Accepted: 08/27/2014] [Indexed: 11/22/2022]
Abstract
Dimercaptopropanesulfonic acid (DMPS) has been approved for the treatment of arsenic poisoning through promoting arsenic excretion and modulating arsenic species. To clarify how DMPS regulates the excretion of arsenic species, we investigated the effects of DMPS on the biomethylation of arsenite (As(3+)) in HepG2 cells. In the experiments, we found that DMPS at low concentrations dramatically decreased the content of arsenic in HepG2 cells and inhibited the cellular methylation of As(3+). Three aspects, the expression of human arsenic (III) methyltransferase (hAS3MT), the accumulation of cellular reactive oxygen species (ROS) and the in vitro enzymatic methylation of arsenic, were considered to explain the reasons for the inhibition of DMPS in arsenic metabolism. The results suggested that DMPS competitively coordinated with As(3+) and monomethylarsonous acid (MMA(3+)) to inhibit the up-regulation of arsenic on the expression of hAS3MT and block arsenic involving in the enzymatic methylation. Moreover, DMPS eliminated arsenic-induced accumulation of ROS, which might contribute to the antidotal effects of DMPS on arsenic posing.
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Li X, Geng Z, Chang J, Wang S, Song X, Hu X, Wang Z. Identification of the third binding site of arsenic in human arsenic (III) methyltransferase. PLoS One 2013; 8:e84231. [PMID: 24391919 PMCID: PMC3877260 DOI: 10.1371/journal.pone.0084231] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Accepted: 11/21/2013] [Indexed: 01/15/2023] Open
Abstract
Arsenic (III) methyltransferase (AS3MT) catalyzes the process of arsenic methylation. Each arsenite (iAs3+) binds to three cysteine residues, methylarsenite (MMA3+) binds to two, and dimethylarsenite (DMA3+) binds to one. However, only two As-binding sites (Cys156 and Cys206) have been confirmed on human AS3MT (hAS3MT). The third As-binding site is still undefined. Residue Cys72 in Cyanidioschyzon merolae arsenite S-adenosylmethyltransferase (CmArsM) may be the third As-binding site. The corresponding residue in hAS3MT is Cys61. Functions of Cys32, Cys61, and Cys85 in hAS3MT are unclear though Cys32, Cys61, and Cys85 in rat AS3MT have no effect on the enzyme activity. This is why the functions of Cys32, Cys61, and Cys85 in hAS3MT merit investigation. Here, three mutants were designed, C32S, C61S, and C85S. Their catalytic activities and conformations were determined, and the catalytic capacities of C156S and C206S were studied. Unlike C85S, mutants C32S and C61S were completely inactive in the methylation of iAs3+ and active in the methylation of MMA3+. The catalytic activity of C85S was also less pronounced than that of WT-hAS3MT. All these findings suggest that Cys32 and Cys61 markedly influence the catalytic activity of hAS3MT. Cys32 and Cys61 are necessary to the first step of methylation but not to the second. Cys156 and Cys206 are required for both the first and second steps of methylation. The SC32 is located far from arsenic in the WT-hAS3MT-SAM-As model. The distances between SC61 and arsenic in WT-hAS3MT-As and WT-hAS3MT-SAM-As models are 7.5 Å and 4.1 Å, respectively. This indicates that SAM-binding to hAS3MT shortens the distance between SC61 and arsenic and promotes As-binding to hAS3MT. This is consistent with the fact that SAM is the first substrate to bind to hAS3MT and iAs is the second. Model of WT-hAS3MT-SAM-As and the experimental results indicate that Cys61 is the third As-binding site.
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Affiliation(s)
- Xiangli Li
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, PR China
| | - Zhirong Geng
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, PR China
- * E-mail: (ZW); (ZG)
| | - Jiayin Chang
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, PR China
| | - Shuping Wang
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, PR China
| | - Xiaoli Song
- School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou, PR China
| | - Xin Hu
- Modern Analysis Center of Nanjing University, Nanjing, PR China
| | - Zhilin Wang
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, PR China
- * E-mail: (ZW); (ZG)
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