ASU professor to study the structural biology of photosynthetic supercomplexes with NSF CAREER Award

The proposed work targets the most essential function carried out by living organisms — using light to create food and oxygen

January 24, 2022

Plants, algae and cyanobacteria use photosynthesis to produce oxygen and reduce carbon, like carbohydrates, which builds and fuels our entire biosphere.

“Supercomplexes are associations between antennae proteins and photochemical reaction centers that exist in all photosynthetic organisms,” said Yuval Mazor, an assistant professor in the School of Molecular Sciences and the Biodesign Institute’s Center for Applied Structural Discovery. Portrait of Yuval Mazor, an assistant professor in ASU's School of Molecular Sciences and the Biodesign Institute. Yuval Mazor is an assistant professor in the School of Molecular Sciences and the Biodesign Institute at ASU. Photo by Mary Zhu/ASU Download Full Image

Mazor was recently awarded a prestigious Faculty Early Career Development (CAREER) Award from the National Science Foundation. The program identifies the nation’s most promising young faculty members and provides them with funding to pursue outstanding research, excellence in teaching and the integration of education and research. Often, these awards spur the creativity of the faculty member, helping to set them on an innovative career path.

“Yuval’s proposed work targets the most essential function carried out by living organisms — using light to create food and oxygen,” said Professor Tijana Rajh, director of the School of Molecular Sciences, which is part of The College of Liberal Arts and Sciences.

“The ability to observe large numbers of individual complexes performing their functions using cryogenic electron microscopy (cryo-EM) will elucidate the differences enabling the same protein complex to carry out different functions in plants, and will shed light on how changing structures and complex components correlate with switching in their primary role to make food and oxygen.”

Rajh added, “It is so exciting to see how rapidly evolving new approaches in cryo-EM are revolutionizing our abilities to understand the role of structure for different functions carried out by essential protein supercomplexes, such as photosystem I.”

Mazor group

From left to right: Alan Nisanov, undergraduate research student; Christopher Gorski, grad student; Zhen Da, grad student; Yuval Mazor; Zach Dobson, grad student; Jin Li, grad student; Halima Khatun, grad student; and Randel Maqdisi, undergraduate research student. Photo by Mary Zhu/ASU

Understanding photosynthesis

There are two pigment-protein complexes that orchestrate the primary light reactions in oxygenic photosynthesis: photosystem I (PSI) and photosystem II (PSII). Understanding how these photosystems work their magic is one of the long-sought goals of science.

“The long-term goal of this project is to develop a high-level understanding of the function of photosynthetic supercomplexes together with the ability to manipulate their properties in photosynthetic organisms,” Mazor said.

To achieve this goal, Mazor’s group plans to discover new structures of the PSI complex in eukaryotes. PSI is one of the most complicated assemblies in nature. Like many large cellular structures, PSI interacts with many cellular factors to carry out distinct functions. These functions are still not clearly explained in our structural description of PSI.

This proposal tackles this issue using cryo-EM supplemented with functional analysis to discover supercomplexes adjusting energy flow around PSI in plants.

Electron flow in photosynthesis follows two main modes: linear electron flow or cyclic electron flow (LEF or CEF respectively). By balancing these two pathways, photosynthetic organisms adapt the output of the photosynthetic machinery to cellular needs. The potential for engineering photosynthetic organisms to achieve higher productivity or to synthesize specific chemicals is great but requires better basic understanding of this machinery.

The balance between CEF and LEF affects both the ATP/NADPH (energy storage and electron carrier/donor molecule) synthesized in the cell and the induction of photoprotective mechanisms. These mechanisms are a major response to cellular stress.

“By determining high-resolution structures of these complexes, our mechanistic understanding of the basic systems controlling electron flow modes in photosynthesis will greatly improve. I’m very happy to receive this award, and we are looking forward to doing the research,” Mazor said.

PSI structure

Overall structure of PSI-IsiA supercomplex.

Broader impacts

As part of this proposal, one graduate student and a number of undergrad students will receive broad scientific training. Summer internships for veterans will also be offered in the lab to facilitate reintroduction into civilian life through science.

In order to increase public access, virtual reality renderings of supercomplexes and thylakoid membranes will be generated. These renderings will be a great conduit to raise interest in science in general, and photosynthesis in particular, by bringing very complicated systems to life. These renderings will be incorporated into the biochemistry and photosynthesis courses taught by Mazor as an aid in visualizing advanced concepts, such as electron transport, excitation energy transfer and the dynamic nature of protein interactions.

Understanding the complexity and functions of PSI supercomplexes will ultimately help to ensure that we have a stable energy supply on Earth.

Jenny Green

Clinical associate professor, School of Molecular Sciences


All in the family: ASU film professor brings ancestor's legend to the screen

January 24, 2022

Peter Murrieta grew up hearing stories about his ancestor Joaquin Murrieta, also known as the Robin Hood of the West, from his relatives — about how clever and resourceful Joaquin was, how he buried gold all over California and how he defended the less fortunate. Males in every generation of Peter Murrieta’s family, he says, were named Joaquin — including Peter’s father and his own first-born son.

“Whenever life knocked the Murrietas down,” Peter told an interviewer, “we had the legend of Joaquin to help us get back up again.”  Emmy award-winning producer and writer Peter Murrieta. Photo by Jarod Opperman/ASU Download Full Image

Now, Peter, an Emmy Award-winning television screenwriter and the deputy director of The Sidney Poitier New American Film School at ASU, is sharing Joaquin’s story with the wider world. In this conversation, the Tucson native talks about “Blood and Gold: The Legend of Joaquin Murrieta,” the book he co-authored with Jeffrey J. Mariotte and is adapting for the screen, as well as about his path to becoming a writer and the life-changing power of teachers.

Question: What were some shows/movies/books that were important to you growing up?

Answer: One of my favorite books as a child was this book called “There’s a Monster at the End of This Book.” It’s a Grover Sesame Street book. I found it really wonderful as a kid. Forgot totally about it. And then when I was a grownup, I was at a yard sale and saw it, and I was like, “Oh, my God, I remember that book!” And when I re-read it as a grownup, I realized how much it had informed my comedy, the way I look at art and all that stuff. It was very interesting, very meta, kind of funny. The big joke is on the main protagonist at the end. All these kinds of interesting things. 

As I got older, I found comic books, and that was a big piece of my literature growing up. I always was interested in the side characters. I was always interested in Robin, I was interested in this alternate universe version of Superman where he was older and married. So I was always gravitating toward (the unsung characters). Even though they were in books, they just weren’t the main characters.

Q: Where do you think that impulse came from? 

A: I totally think it comes from lack of representation. It’s interesting. People my age, there’s a lot of activists that — it’s a sword that cuts both ways, I’d say that. Because, as a kid, I didn't have it. I wish I did, but I didn't. But I created it myself. I went, "OK, Robin has dark hair and he’s a kid. Alright, I can work with that, that can be me." So I think I just put it on things. I imprinted it. 

I had this conversation with this producer that I’m working on something with — who’s also a comic book fan, also my age, and he’s gay — and he was talking about the same thing: going to the comic book stores and finding your way into it in that way. When I say it cuts two ways, I think in a weird way, that was very wonderful to open me up to imagining things the way I wanted them. I do believe the reports and the studies and all the things we know now about people seeing themselves and how important it is, so I don’t want to diminish that at all. But I do think that there are ways to make good out of things. 

I guess it cuts both ways too, because now, maybe it’s because of my age, I hear lots of people saying, “Well, I created such and such show because I never could see myself growing up,” and as someone who’s been making shows for 25 years, and other people like me who’ve been making shows for 25 years, it’s like, maybe you needed to watch my show earlier. Maybe it would have been on, and maybe it would have stayed on. I don’t know. So I think the fight is the fight, and we keep fighting.

Illustration of Joaquin Murrieta, "the Robin Hood of the West," by Thomas Armstrong, circa 1851.

A drawing of Joaquin Murrieta by Thomas Armstrong, circa 1851.

Q: You grew up hearing the Joaquin Murrieta stories, right?

A: From my dad and my grandparents and my uncles and my aunts — these are all the kinds of stories we were told when we were kids. He was a hero in our family to be looked up to. There’s some fiction in the book, because of course he’s a legend, and it’s hard to pin him down. The thing that helped me see what the book could be, for anybody that’s reading it, was creating the relationship with the man who would later hunt him down. That was really a sort of authorial decision in a way to try to give an arc and an understanding to that.

Q: How did you start writing, or start telling stories?

A: I have a memory in like fourth grade of writing a story — I think we were given a prompt of lemonade, or lemons, or something like that. I remember turning mine in. It was sheets of paper you’re supposed to just fill, very easy. But I remember the teacher asking me to read it. And I can still remember that the title of it was “The Day That It Rained Lemonade.” And I think I read it, and I really wasn’t sure why. And then I think later, there was an open house, back-to-school night — not the parent-teacher night, but the one where you go with your parents. And, you know, the teacher displays things. I think at that moment, I understood, because I saw the other stories ... and I guess I realized, wow, I didn’t think that what I thought of was different that much, but I guess it was. And I think that’s a dim memory of the beginning of that.

Q: The influence of teachers is so powerful.

A: It’s incredible. The other teacher was Donna Swain, who was a professor at the University of Arizona. She really told me I was a writer. She was like, “You need to do this.” And I wasn’t that interested in it. 

Q: Why not?

A: It felt hard and it felt like something that no one I knew did, and it felt like a mystery. I was on track to be a high school English teacher. I was very excited about that idea, at the time.

And it was hard. I was right. It’s funny when you think about these things you don’t try because they’re hard, and you think about the things you do try because they’re hard. I guess that’s where we find courage.

Q: You didn’t land that far from being a high school English teacher.

A: I didn’t. It took me a long time, though. Took me a long time.

Q: Is (the show) “Mr. Iglesias” based on what you were going to be? 

A: “Mr. Iglesias” is based on the fact that Gabe (Iglesias) had a teacher who affected him in high school — the only teacher that thought he was worth anything. It was his speech/communications person. So it was a conversation he had with Kevin Hench, the creator of the show, about what would have happened if Gabe hadn’t become a standup comic, and Gabe was like, "You know, I always thought I’d be a teacher." And I said, “Oh that’s funny, I always thought I was going to be a teacher.” 

Q: You posted a great Bad Bunny quote on social media: “Nobody asks a gringo artist to change. This is who I am. This is my music. This is my culture. If you don’t like it, don’t listen to me.” Have you always felt that way?

A: No! I’d say this is recent, as in four or five years. I’d say the beginning of my career, in television anyway, was a lot of trying to appeal and trying to explain. And the last four or five years, it’s been more like, “I think I’m just going to do what I do, and if you don’t get it, that’s cool.” And (Bad Bunny) is so amazing, I could talk about him forever. The fact that he’s Bad Bunny, the fact that he didn’t choose a Spanish name but chose to sing in Spanish. The fact that he’s all about everybody. He’s all about gender fluidity. And he just quietly does what he does. And you can enjoy it or not. It’s just great. I don’t ever feel like he’s teaching me. I just feel like he’s doing his thing. And when I saw that quote, it just resonated for me. Because I do think we should do more of that. We should do more of like, here’s who we are, here’s our authentic selves, and then hope people like it, hope people enjoy it, hope people are entertained by it, I guess.

Q: What do you like about being at ASU?

A: I love the culture that asks us to do things with intention and lift up those around us, and I like that in my school we’re about getting people ready. And I just think that keeps me there. I think I ask myself that question like every third Sunday when I’m flying. It’s a question I think about a lot. I think I’m inspired by the students. I’m inspired by my colleagues. And I don't just say that. A student made a video for freshman orientation class that I posted this morning on Facebook that was just amazing. So it’s literal inspiration, where you’re like, "Wow, I better be on my game, I better not sleep on any of this, because they’re coming."

Q: They’re coming like, they are the future?

A: They’re the future and they’re the competition. Both. They’re coming. And I think that’s also part of my secret agenda is to overwhelm my section of Hollywood with tons and tons of people who are trained, who have voices, who are from underserved communities, and just make it just kind of undeniable that that’s what’s happening next. Just undeniable. Instead of asking, everybody just shows up.

Q: Anything you’d like to add?

A: The henchman comic book that I did last year with Starburns Press and “Blood and Gold” with Sundown Press are just two great examples of stories that I’ve always wanted to tell, stories that I've pitched in Hollywood that have been not bought, rejected, not listened to, for whatever reason. The idea of not stopping that from letting you tell your story is super important to me. It’s super important to me that you keep in mind that if your job is to tell a story and you want an audience, go find it. Don’t wait for permission.

Deborah Sussman

Communications and media specialist, Herberger Institute for Design and the Arts