Targeting of many polytopic proteins to the inner membrane of prokaryotes occurs via an essential signal recognition particle-like pathway. FtsY, the Escherichia coli homolog of the eukaryotic signal recognition particle receptor ␣-subunit, binds to membranes via its amino-terminal AN domain. We demonstrate that FtsY assembles on membranes via interactions with phosphatidylethanolamine and with a trypsin-sensitive component. Both interactions are mediated by the AN domain of FtsY. In the absence of phosphatidylethanolamine, the trypsin-sensitive component is sufficient for binding and function of FtsY in the targeting of membrane proteins. We propose a two-step mechanism for the assembly of FtsY on the membrane similar to that of SecA on the E. coli inner membrane.In Escherichia coli, most integral membrane proteins are targeted to the inner membrane via the signal recognition particle (SRP) 1 (1-4), a particle composed of Ffh and 4.5 S RNA (5, 6). SRP promotes co-translational targeting of nascent polypeptide chains via an interaction with FtsY, the membrane-associated SRP receptor (7,8). Although the targeting steps are distinct from those of the SecB secretory pathway (9, 10), both pathways converge at a common translocation pore in the membrane that comprises SecY, SecE, and SecG (7,11).The components of the SRP pathway in E. coli closely resemble those of eukaryotes both in sequence (12-15) and in functional interactions (5,6,16,17). An interesting divergence is observed in the mechanism of assembly of the SRP receptors onto membranes. In eukaryotes, the transmembrane ␤-subunit (SR␤) of the SRP receptor anchors the peripheral membrane ␣-subunit (SR␣) on the ER membrane through an interaction between the GTP-binding domain of SR␤ (18) and the aminoterminal domain of SR␣ (19). No homolog of SR␤ has been identified in the E. coli genome sequence. Although SR␣ and FtsY are homologous over two-thirds of their lengths, the amino-terminal domains are highly divergent (14,15). Instead of the SR␤-binding domain found in SR␣, FtsY has a highly negatively charged A region at the amino terminus (arbitrarily defined as amino acids 1-196) (20) that, together with the central N region (amino acids 197-280), forms the minimum domain sufficient for assembly on the E. coli inner membrane (21). Mutations that abolish attachment of FtsY to the E. coli inner membrane interfere with protein targeting and cell viability (8,22).Both bilayer and non-bilayer phospholipids have been implicated in the assembly and activity of several components of the secretory pathway in E. coli, including SecA (23, 24) and the translocon (25). Recent investigations have demonstrated the presence of a region in the carboxyl-terminal region of FtsY that may be regulated by binding to anionic phospholipids (26). It was also speculated that a second lipid-binding site exists in the amino-terminal region of FtsY (26). Here we show that the previously defined membrane-binding domain of FtsY binds liposomes containing the zwitterionic phospholipid phosphat...

The use of gamified learning interventions is expanding in postsecondary education as a means to improve students' motivation and learning outcomes. Virtual laboratory simulations have been used in science education to supplement students' learning, as well as to increase engagement with course material. Due to COVID‐19, many instructors sought to replace or supplement hands‐on ‘wet‐lab’ work in an online environment. In this paper, we explored how the use of head‐mounted display technology in two laboratory simulations impacts learner motivation and learning outcomes. We used a mixed‐methods approach to analyze the experience of 39 undergraduate participants, examining test scores pre‐ and postsimulation, qualitative feedback, and quantitative experience ratings. The head‐mounted display technology was described as easy to use, with eye strain identified as a common occurrence. Participants had increased test scores following the laboratory simulations, with no significant difference between simulation groups. Very positive self‐reported measures of motivation and learner engagement were documented. Ninety‐one percent of participants agreed that virtual reality laboratory simulation would be a good supplement to regular teaching modalities. Overall, our results suggest that immersive virtual reality laboratory simulations experienced through head‐mounted display technology can be used to enhance learning outcomes and increase learner motivation.

Increasing student participation in science is an ongoing challenge for many universities. In this active learning workshop, centered on inquiry and teamwork, we introduce highschool students to biochemistry and molecular biology techniques using a murder mystery activity. During this intensive 3 hr workshop, we engage students in a murder scenario entitled "The Case of the Silenced Scientist." A commercially available DNA fingerprinting kit was used as a basis to create a customized scenario whereby students collaborate with one another to solve a murder mystery. Through analysis of DNA samples taken from the crime scene and suspects, students can identify the murderer while developing technical, teamwork, and critical thinking skills. Emphasis is placed on teamwork by immersing students in the collaborative process of research inquiry. Though short in duration, this workshop aims to build student relationships to science through creativity and exploration. In this article, we describe the key customized applications of this workshop as a blueprint for science recruitment. We focus on the workshop facilitators' perceived learning impact on students.

No abstract

No abstract