Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 3 of 3

Full-Text Articles in Physical Sciences and Mathematics

Mechanism Of Ubiquitin Ligation And Lysine Prioritization By A Hect E3, Hari B. Kamadurai, Yu Qiu, Alan Deng, Joseph S. Harrison, Chris Macdonald, Marcelo Actis, Patrick Rodrigues, Darcie J. Miller, Judith Souphron, Steven M. Lewis, Igor Kurinov, Naoaki Fujii, Michal Hammel, Robert Piper, Brian Kuhlman, Brenda A. Schulman Aug 2013

Mechanism Of Ubiquitin Ligation And Lysine Prioritization By A Hect E3, Hari B. Kamadurai, Yu Qiu, Alan Deng, Joseph S. Harrison, Chris Macdonald, Marcelo Actis, Patrick Rodrigues, Darcie J. Miller, Judith Souphron, Steven M. Lewis, Igor Kurinov, Naoaki Fujii, Michal Hammel, Robert Piper, Brian Kuhlman, Brenda A. Schulman

College of the Pacific Faculty Articles

Ubiquitination by HECT E3 enzymes regulates myriad processes, including tumor suppression, transcription, protein trafficking, and degradation. HECT E3s use a two-step mechanism to ligate ubiquitin to target proteins. The first step is guided by interactions between the catalytic HECT domain and the E2∼ubiquitin intermediate, which promote formation of a transient, thioester-bonded HECT∼ubiquitin intermediate. Here we report that the second step of ligation is mediated by a distinct catalytic architecture established by both the HECT E3 and its covalently linked ubiquitin. The structure of a chemically trapped proxy for an E3∼ubiquitin-substrate intermediate reveals three-way interactions between ubiquitin and the bilobal HECT …


Exploring The Roles Of Nucleobase Desolvation And Shape Complementarity During The Misreplication Of O6-Methylguanine, Delia Chavarria, Andrea Ramos Serrano, Ichiro Hirao, Anthony J. Berdis Sep 2011

Exploring The Roles Of Nucleobase Desolvation And Shape Complementarity During The Misreplication Of O6-Methylguanine, Delia Chavarria, Andrea Ramos Serrano, Ichiro Hirao, Anthony J. Berdis

Chemistry Faculty Publications

O6-methylguanine is a miscoding DNA lesion arising from the alkylation of guanine. This report uses the bacteriophage T4 DNA polymerase as a model to probe the roles hydrogen-bonding interactions, shape/size, and nucleobase desolvation during the replication of this miscoding lesion. This was accomplished by using transient kinetic techniques to monitor the kinetic parameters for incorporating and extending natural and non-natural nucleotides. In general, the efficiency of nucleotide incorporation does not depend on the hydrogen-bonding potential of the incoming nucleotide. Instead, nucleobase hydrophobicity and shape complementarity appear to be the preeminent factors controlling nucleotide incorporation. In addition, shape complementarity plays a …


From Gene Mutation To Protein Characterization, David A. Moffet Mar 2009

From Gene Mutation To Protein Characterization, David A. Moffet

Chemistry and Biochemistry Faculty Works

A seven-week “gene to protein” laboratory sequence is described for an undergraduate biochemistry laboratory course. Student pairs were given the task of introducing a point mutation of their choosing into the well studied protein, enhanced green fluorescent protein (EGFP). After conducting literature searches, each student group chose the mutation they wanted to introduce into EGFP. Students designed their sequence-specific mutagenic primers and constructed their desired mutation. The resulting EGFP mutant proteins were expressed in E. coli, purified and characterized. This laboratory sequence connected the major concepts of molecular biology and biochemistry, while incorporating the thrill of novel discovery in …