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Ole Kristensen

Publications and source records attributed to Ole Kristensen.

21 records · Page 2Linked to original sources

Expression, refolding and crystallization of Aquifex aeolicus elongation factor P.

Elongation factor P is a universally conserved protein stimulating peptidyltransferase activity during protein synthesis. The factor is sensitive to classical inhibitors of the ribosomal peptidyltransferase activity and is possibly involved in alignment of the substrate tRNAs in the catalytic centre of 70S ribosomes. Elongation factor P from the thermophilic Aquifex aeolicus was overexpressed as a soluble protein in Escherichia coli and crystallized. A fast generally applicable refolding protocol was developed to improve crystal quality and circumvent strong binding of oligonucleotides to the protein. Diffraction data collected to 2.7 A resolution present twinning.

Bacterial Proteins↗

Cessation of smoking after first-ever stroke: a follow-up study.

BACKGROUND AND PURPOSE: Cessation of smoking is widely recommended in patients with stroke to reduce the risk of myocardial infarction and recurrent stroke, but little is known regarding how patients modify their smoking habits after a stroke. We used data from a prospective follow-up study to assess modification of smoking habits and to identify predictors of persistent smoking after first-ever stroke. METHODS: All patients admitted to the only neurology department of Funen County (465 000 inhabitants) with first-ever stroke from August 1, 1999, to January 31, 2001, were prospectively identified. A comprehensive structured interview was completed both during hospitalization and at 6-month follow-up. The interview comprised questions on education, occupation, marital status, lifestyle, concomitant diseases, and functional disability. We estimated the relative risk of persistent smoking at follow-up using unconditional logistic regression. RESULTS: We identified 734 patients with a first-ever stroke in the study period. One hundred three patients (14%) died in the 6-month period after their admission. A total of 511 patients (81%) who participated in the interview both on admission and at follow-up were included in the present study. Among 198 patients (38.7%) who were current smokers on admission, 43 patients (21.7%) gave up smoking within 6 months of suffering a stroke. Sex, functional status, and sociodemographic characteristics were independently associated with persistent smoking. CONCLUSIONS: Our results suggest that more efficient antismoking counseling is required to reduce the proportion of persistent smokers after stroke. This counseling should take into account the increased risk of persistent smoking in men, patients with no disability, blue-collar workers, and patients living alone.

Adult↗

Is tRNA binding or tRNA mimicry mandatory for translation factors?

tRNA is the adaptor in the translation process. The ribosome has three sites for tRNA, the A-, P-, and E-sites. The tRNAs bridge between the ribosomal subunits with the decoding site and the mRNA on the small or 30S subunit and the peptidyl transfer site on the large or 50S subunit. The possibility that translation release factors could mimic tRNA has been discussed for a long time, since their function is very similar to that of tRNA. They identify stop codons of the mRNA presented in the decoding site and hydrolyse the nascent peptide from the peptidyl tRNA in the peptidyl transfer site. The structures of eubacterial release factors are not yet known, and the first example of tRNA mimicry was discovered when elongation factor G (EF-G) was found to have a closely similar shape to a complex of elongation factor Tu (EF-Tu) with aminoacyl-tRNA. An even closer imitation of the tRNA shape is seen in ribosome recycling factor (RRF). The number of proteins mimicking tRNA is rapidly increasing. This primarily concerns translation factors. It is now evident that in some sense they are either tRNA mimics, GTPases or possibly both.

Molecular Mimicry↗