{"doi":"10.17615/6a6d-q814","title":"Effect of guanine nucleotides on the conformation and stability of chloroplast elongation factor Tu","abstract":"The effect of guanine nucleotides and kirromycin on the conformation and stability of the chloroplast elongation factor Tu (EF-Tuchl) from Euglena gracilis has been investigated. Free EF-Tuchl is quite thermolabile but the protein is greatly stabilized by guanine nucleotides. The temperature dependence of the thermal inactivation of EF-Tuchl was used to calculate the amount of stabilization energy conferred by the guanine nucleotides. GDP increases the activation energy for the denaturation process by 77 kcal/mol while GTP increases the activation energy by 51 kcal/mol. The difference in heat stability of free EF-Tuchl and the EF-Tuchl.GDP complex was used to determine a dissociation constant of 1.3 x 10(-7) M at 37 degrees C. The temperature dependence of the dissociation constant allowed the calculation of a delta H degree obsd of -55 kcal/mol and a delta S degree obsd of -146 cal/(mol degree) for GDP binding to EF-Tuchl.EF-Tuchl was found to have a trypsin-sensitive region similar to that observed for Escherichia coli EF-Tu. This loop region was protected by GTP and kirromycin but not by GDP.","journal":"UNC Libraries","year":2021,"id":230591,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":0,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9544,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2021-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":293662,"name":"The University of North Carolina at Chapel Hill University Libraries","orcid":null,"position":0,"is_corresponding":true}],"reference_count":0,"raw_metadata":null,"created_at":"2026-07-18T23:55:09.211909Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}