Elucidation of the electron transfer environment in the MMOR FAD-binding domain from Methylosinus sporium 5.

By facilitating electron transfer to the hydroxylase diiron center, MMOR-a reductase-serves as an essential component of the catalytic cycle of soluble methane monooxygenase. Here, the X-ray structure analysis of the FAD-binding domain of MMOR identified crucial residues and its influence on the catalytic cycle.

Efficacy and Safety of Vacuum-Assisted Excision for Benign Breast Mass Lesion: A Meta-Analysis.

Background and Objective: Breast mass lesions are common; however, determining the malignant potential of the lesion can be ambiguous. Recently, to evaluate breast mass lesions, vacuum-assisted excision (VAE) biopsy has been widely used for both diagnostic and therapeutic purposes. This study aimed to investigate the therapeutic role of VAE. Materials and Methods: Relevant articles were obtained by searching PubMed and EMBASE on 3 September 2021. Meta-analyses were performed using odds ratios and proportions. To assess heterogeneity, we conducted a subgroup analysis and meta-regression tests. Results: Finally, 26 studies comprising 18,170 patients were included. All of these were observational studies. The meta-analysis showed that the complete resection rate of VAE was 0.930. In the meta-regression test, there was no significant difference. The meta-analysis showed a recurrence rate of 0.039 in the VAE group. The meta-regression test showed no statistical significance. Postoperative hematoma, pain, and ecchymosis after VAE were 0.092, 0.082, and 0.075, respectively. Conclusion: VAE for benign breast lesions showed favorable outcomes with respect to complete resection and complications. This meta-analysis suggested that VAE for low-risk benign breast lesions is a reasonable option for both diagnostic and therapeutic purposes.

MMOD-induced structural changes of hydroxylase in soluble methane monooxygenase.

Soluble methane monooxygenase in methanotrophs converts methane to methanol under ambient conditions. The maximum catalytic activity of hydroxylase (MMOH) is achieved through the interplay of its regulatory protein (MMOB) and reductase. An additional auxiliary protein, MMOD, functions as an inhibitor of MMOH; however, its inhibitory mechanism remains unknown. Here, we report the crystal structure of the MMOH-MMOD complex from Methylosinus sporium strain 5 (2.6 Å). Its structure illustrates that MMOD associates with the canyon region of MMOH where MMOB binds. Although MMOD and MMOB recognize the same binding site, each binding component triggers different conformational changes toward MMOH, which then respectively lead to the inhibition and activation of MMOH. Particularly, MMOD binding perturbs the di-iron geometry by inducing two major MMOH conformational changes, i.e., MMOH ß subunit disorganization and subsequent His147 dissociation with Fe1 coordination. Furthermore, 1,6-hexanediol, a mimic of the products of sMMO, reveals the substrate access route.