Biology subjects

Yumoto, F.

Publications and source records attributed to Yumoto, F..

6 recordsLinked to original sources

bioRxiv2022

Mapping Protein Dynamics at High-Resolution with Temperature-Jump X-ray Crystallography

Understanding and controlling protein motion at atomic resolution is a hallmark challenge for structural biologists and protein engineers because conformational dynamics are essential for complex functions such as enzyme catalysis and allosteric regulation. Time-resolved crystallography offers a window into protein motions, yet without a universal perturbation to initiate conformational changes the method has been limited in scope. Here we couple a solvent-based temperature jump with time-resolved crystallography to visualize structural motions in lysozyme, a dynamic enzyme. We observed widespread atomic vibrations on the nanosecond timescale, which evolve on the sub-millisecond timescale into localized structural fluctuations that are coupled to the active site. An orthogonal perturbation to the enzyme, inhibitor binding, altered these dynamics by blocking key motions that allow energy to dissipate from vibrations into functional movements linked to the catalytic cycle. Because temperature-jump is a universal method for perturbing molecular motion, the method demonstrated here is broadly applicable for studying protein dynamics.

biophysics↗

bioRxiv2021

Structural insight into host plasma membrane association and assembly of HIV-1 Matrix protein

HIV-1 continues to be a global health concern since AIDS was first recognized by the World Health Organization (WHO). It is estimated that there were 38 million people infected with HIV-1 and 1.5 million deaths in 2019 alone. A better understanding of the details of the HIV late-stage life cycle, involving Pr55Gag attachment to the membrane for the further oligomerization to release virion, will provide us new avenues for potential treatment. Inositol hexakisphosphate (IP6) is an abundant endogenous cyclitol molecule and its binding was linked to the oligomerization of Pr55Gag via the MA domain. However, the binding site of IP6 on MA was unknown and the structural details of this interaction were missing. Here, we present three high-resolution crystal structures of the MA domain in complex with IP6 molecules to reveal its binding mode. Additionally, extensive Differential Scanning Fluorimetry analysis combined with cryo- and ambient-temperature X-ray crystallography and computational biology identify the key residues that participate in IP6 binding. Our data provide novel insights about the multilayered HIV-1 virion assembly process that involves the interplay of IP6 with PIP2, a phosphoinositide essential for the membrane binding of Pr55Gag. IP6 and PIP2 have neighboring alternate binding sites within the same highly basic region (residues 18-33). This indicates that IP6 and PIP2 bindings are not mutually exclusive and may play a key role in coordinating virion particles membrane localization. Based on our three different IP6-MA complex crystal structures, we propose a new model that involves the IP6 coordination of the oligomerization of outer MA and inner CA domain 2D layers during assembly and budding.

microbiology↗

bioRxiv2020

Size matters: optimal mask diameter and box size for single-particle cryogenic electron microscopy

Recently it has been demonstrated that single-particle cryogenic electron microscopy (cryo-EM) at 200 keV is capable of determining protein structures, including those smaller than 100 kDa, at sub-3.0 [A] resolutions, without using significant defocus or a phase plate. However, the majority of near-atomic resolution cryo-EM structures has been determined using 300 keV. Consequently, many typical parameter settings for the cryo-EM computational image processing steps, especially those associated with the contrast transfer function, are based on the accumulated experience of 300 kV cryo-EM. We have therefore revised these parameters, established theoretical bases for criteria to find an optimal mask diameter and box size for a given dataset irrespective of acceleration voltage or protein size, and proposed a protocol. Considering the defocus distributions of the datasets, merely optimizing the mask diameters and box sizes yielded meaningful resolution improvements for the reconstruction of < 200 kDa proteins using 200 kV cryo-EM.

molecular biology↗

bioRxiv2019

An integrated approach unravels a crucial structural property for the function of the insect steroidogenic Halloween protein Noppera-bo

Ecdysteroids are the principal insect steroid hormones essential for insect development and physiology. In the last 18 years, several enzymes responsible for ecdysteroid biosynthesis, encoded by Halloween genes, have been identified and well characterized, both genetically and biochemically. However, none of these proteins have yet been characterized at the tertiary structure level. Here, we report an integrated in silico, in vitro, and in vivo analyses of the Halloween glutathione S-transferase (GST) protein, Noppera-bo (Nobo). We determine crystal structures of Drosophila melanogaster Nobo (DmNobo) complexed with glutathione and 17{beta}-estradiol, a DmNobo inhibitor. 17{beta}-estradiol almost fully occupied the putative ligand-binding pocket, and a prominent hydrogen bond formed between Asp113 of DmNobo and 17{beta}-estradiol. Asp113 is essential for inhibiting DmNobo enzymatic activity by 17{beta}-estradiol, as 17{beta}-estradiol does not inhibit and physically interacts less with the Asp113Ala DmNobo point mutant. Asp113 is highly conserved among Nobo proteins, but not among other GSTs, implying that Asp113 is important for endogenous Nobo function. Indeed, a homozygous nobo allele possessing the Asp113Ala point mutation exhibits embryonic lethality with undifferentiated cuticle structure, a phenocopy of complete loss-of-function nobo homozygotes. These results suggest that the nobo family of GST proteins has acquired a unique amino acid residue, which seems to be essential for binding an endogenous sterol substrate to regulate ecdysteroid biosynthesis. This is the first study to reveal the structural characteristics of insect steroidogenic Halloween proteins. This study also provides basic insight into applied entomology for developing a new type of insecticides that specifically inhibit ecdysteroid biosynthesis.\n\nSignificance StatementInsect molting and metamorphosis are drastic and dynamic biological processes and, therefore, have fascinated many scientists. Ecdysteroids represent one class of insect hormones that are indispensable for inducing molting and metamorphosis. It is well known that proteins responsible for catalyzing ecdysteroid biosynthesis reactions are encoded by \"Halloween\" genes, most of which have names of ghosts and phantoms. However, no studies have focused on the structural properties of these biosynthetic proteins. In this study, we addressed this unsolved issue and successfully unraveled a structural property that is crucial for the function of the fruit fly Halloween protein, Noppera-bo (a Japanese faceless ghost). This is the first study to reveal the structural characteristics of an insect steroidogenic Halloween protein.

biochemistry↗

bioRxiv2019

Comparing serial X-ray crystallography and microcrystal electron diffraction (MicroED) as methods for routine structure determination from small macromolecular crystals

Innovative new crystallographic methods are facilitating structural studies from ever smaller crystals of biological macromolecules. In particular, serial X-ray crystallography and microcrystal electron diffraction (MicroED) have emerged as useful methods for obtaining structural information from crystals on the nanometer to micron scale. Despite the utility of these methods, their implementation can often be difficult, as they present many challenges not encountered in traditional macromolecular crystallography experiments. Here, we describe XFEL serial crystallography experiments and MicroED experiments using batch-grown microcrystals of the enzyme cyclophilin A (CypA). Our results provide a roadmap for researchers hoping to design macromolecular microcrystallography experiments, and they highlight the strengths and weaknesses of the two methods. Specifically, we focus on how the different physical conditions imposed by the sample preparation and delivery methods required for each type of experiment effect the crystal structure of the enzyme.

biophysics↗

bioRxiv2019

Serial femtosecond X-ray diffraction of HIV-1 Gag MA-IP6 microcrystals at ambient temperature

The Human immunodeficiency virus-1 (HIV-1) matrix (MA) domain is involved in the highly regulated assembly process of the virus particles that occur at the host cells plasma membrane. High-resolution structures of the MA domain determined using cryo X- ray crystallography have provided initial insights into the possible steps in the viral assembly process. However, these structural studies have relied on large and frozen crystals in order to reduce radiation damage caused by the intense X-rays. Here, we report the first XFEL study of the HIV-1 MA domains interaction with inositol hexaphosphate (IP6), a phospholipid headgroup mimic. We also describe the purification, characterization and microcrystallization of two MA crystal forms obtained in the presence of IP6. In addition, we describe the capabilities of serial femtosecond X-ray crystallography (SFX) using X-ray free-electron laser (XFEL) to elucidate the diffraction data of MA-IP6 complex microcrystals in liquid suspension at ambient temperature. Two different microcrystal forms of MA-IP6 complex both diffracted to beyond 3.5 [A] resolution, demonstrating the feasibility of using SFX to study the complexes of MA domain of HIV-1 Gag polyprotein with IP6 at near-physiological temperatures. Further optimization of the experimental and data analysis procedures will lead to better understanding of the MA domain of HIV-1 Gag and IP6 interaction at high resolution and provide basis for optimization of the lead compounds for efficient inhibition of the Gag protein recruitment to the plasma membrane prior to virion formation.

biophysics↗