2024 SIG Officers & Governing Information/Documentation 

Scientific Interest Groups (SIGs) are a vital part of the ACA. There are fourteen SIGs that each represent a particular discipline within the field of crystallography, allowing members to focus on their area of specialty while retaining access to interaction with the entire range of crystallographic techniques and applications. Any member may join however many SIGs they wish. There are no additional fees association with SIG membership.

SIGs exist to give members the opportunity to focus on specialty areas while remaining connected to the entire scope of crystallographic applications. Joining a SIG means finding individuals within the larger network who have common scientific goals, challenges and interests. 

SIGs are responsible for defining the program at annual meetings. Each SIG is charges with organizing at least one half-day session every two years. This is a great opportunity for members to get involved in the ACA at a grass roots level and have a direct impact upon the annual meeting.

By joining the ACA you will have the ability to join as many SIG's as you wish and start to connect with members with similar backgrounds and goals.  When you join a the ACA and SIG's you broaden your network of peers and colleagues and get to enter a unique community of scientists that share your interests and areas of focus.  

Scientific Interest Groups represent the social networking within the ACA designed to:

  • Encourage stimulating scientific exchange

  • Promote collaboration within specific areas of focus throughout the crystallographic community 

  • Provide opportunities to involve new, current and retired members in the organization


Best Practices for Data Analysis & Archiving SIG

The BPDAA SIG was created to join the major effort in the international community to standardize best practices in data analysis and archival and further, to improve community involvement in these best practices.

CHAIR 2023: Aaron Brewster
CHAIR-ELECT 2023/CHAIR 2024: Christine Beavers 
SECRETARY-TREASURER 2022-2023: Charles Hespen


Past Officers:
CHAIR 2022: Lee Daniels
Best Practices SIG Bylaws/Constitution/Governing Documents
BPDAA SIG Reports (Members Only)


Biological Macromolecules SIG

The BioMac SIG focuses on characterization of biological macromolecules, particularly proteins and nucleic acids, using a variety of structural methods such as X-ray crystallography, NMR, EM and SAXS.

CHAIR 2023: Krystle McLaughlin
CHAIR-ELECT 2023/CHAIR 2024: Tori Drago
SECRETARY-TREASURER 2022-2024: Darya Marchany-Rivera


Past Officers:
CHAIR 2022: Sarah Bowman
SECRETARY-TREASURER 2021-2022: Charles Stewart
BioMac SIG Bylaws/Constitution/Governing Documents
BioMac Reports (Members Only)


Canadian Division

As the North American Regional Affiliate of the International Union of Crystallography (IUCr), the ACA plays a significant role in promoting the applications and techniques of crystallography beyond U.S. borders.  The ACA represents all of North and South America to the global scientific community.  Canada is the largest single country outside the United States to contribute to the goals and purposed of the ACA.  The Canadian Division exists therefore to promote the interests of Canadian members and to provide for an elected official to represent these interest on the ACA Council.

CHAIR 2022/2023: V. Nicholas Vukotic
SECRETARY-TREASURER 2023-2024: Joy-Lynn Kobti


Past Officers:
SECRETARY-TREASURER 2021-2022: Nicole Fraser
Canadian Division SIG Bylaws/Constitution/Governing Documents
Canadian Division Reports (Members Only)



The Cryo-EM SIG reflects the rapidly growing interest in use of CryoEM methods within the structural biology community, and perfectly coincides with the recent Nobel Prize in Chemistry awarded to CryoEM pioneers Jacque Dubochet, Joachim Frank, and Richard Henderson.

CHAIR 2023: Yifan Cheng
CHAIR-ELECT 2023/CHAIR 2024: Melanie Ohi
SECRETARY-TREASURER 2022-2023:  Yirui Guo


Past Officers:
CHAIR 2022: Elizabeth Kellogg
Cryo-EM SIG Bylaws/Constitution/Governing Documents
Cryo-EM Reports (Members Only)


Fiber SIG 

The Fiber SIG represents the interests of fiber diffraction specialists and application of fiber diffraction in interdisciplinary studies.  This is a diverse group that employs the use of X-rays, neutrons and elections in diffraction experiments in addition to modern computational molecular modeling approaches. 

This SIG meets every other year, with the next meeting scheduled for 2024.  This SIG also only participates in elections every other year.  The next year to include candidates for this SIG will be the election of 2024 with officers to being their position on January 1, 2025.  

CHAIR 2023/24: Joseph Orgel
SECRETARY-TREASURER 2023-2024: Olga Antipova


Past Officers:
CHAIR 2021/22: Rama S. Madhurapantula
SECRETARY-TREASURER 2021-2022: Joseph Orgel
Fiber SIG Bylaws/Constitution/Governing Documents
Fiber SIG Reports (Members Only)


General Interest SIG

The General Interest SIG provides a forum for presenting topics of general interest that are outside the scope of the other sessions organized by the SIG's at the annual meetings.  The General Interest SIG also has an educational mandate executed in close collaboration with the Education Committee. 

CHAIR 2023: Lisa Katorcha
CHAIR-ELECT 2023/CHAIR 2024: Tim Stachowski
SECRETARY-TREASURER 2022-2023: Mrittika Roy


Past Officers:
CHAIR 2022: Victoria Drago
General Interest SIG Bylaws/Constitution/Governing Documents
General Interest Reports (Members Only)


Industrial SIG

The Industrial SIG represents the interest and activities of industrial scientists for the advancement of all aspects of the application of crystallographic techniques in industrial settings and to promote communication between scientists working with crystallography in the industry. 

CHAIR 2023: Matthew Clifton
CHAIR-ELECT 2023/CHAIR 2024: Chelsy Chesterman 
SECRETARY-TREASURER 2022-2023: Elizabeth Sprague


Past Officers:
CHAIR 2022: Edward (Eddie) Pryor
Industrial SIG Bylaws/Constitution/Governing Documents
Industrial SIG Reports (Members Only)


Light Sources SIG

The domain of the Light Sources SIG is extremely intense X-ray sources such as storage rings and X-ray lasers.  SIG members develop technology and methods to optimize crystal structure determination using these sources, as well as to perform novel experiments and not possible with laboratory X-ray generators.


CHAIR 2023: Denis Keane
CHAIR-ELECT 2022/CHAIR 2023:  Jennifer Wierman

Past Officers:
CHAIR 2022: Dale Kreitler
Light Sources SIG Bylaws/Constitution/Governing Documents
Light Sources SIG Reports (Members Only)


Materials SIG

The Materials SIG promotes the development and application of crystallographic tools and methods necessary to tackle materials problems ranging from catalysis and sustainability to fundamental chemistry and physics. 

CHAIR 2023: Jue Liu
CHAIR-ELECT 2023/CHAIR 2024: Huiwen Ji 
PAST CHAIR : Rebecca McAuliffe


Past Officers:
CHAIR 2021: Vicky Doan-Nguyen
Materials SIG Bylaws/Constitution/Governing Documents
Materials SIG Reports (Members Only)



The MicroED SIG focuses on the method that was developed for the structure determination of proteins from nanocrystals separate from the cryoEM and small molecule SIG. 

INTERIM CHAIR 2023: Brent Nannenga
CHAIR-ELECT 2023/CHAIR 2024: Tamir Gonen
SECRETARY-TREASURER 2022-2023: Brandon Mercado 
MicroED SIG Bylaws/Constitution/Governing Documents


Neutron Scattering SIG 

The Neutron Scattering SIG promotes all aspects of the applications of neutron scattering techniques and those scientists who practice them.   

CHAIR 2023: Keith Taddei
CHAIR-ELECT 2023/CHAIR 2024: Byron Freelon
PAST CHAIR: Alicia Manjon Sanz


Past Officers:
PAST CHAIR 2022: Benjamin Frandsen
Neutrons SIG Bylaws/Constitution/Governing Documents
Neutron Scattering SIG Reports (Members Only)


Powder Diffraction SIG

The Powder Diffraction SIG advocates for scientists that utilize or further develop powder diffraction techniques to investigate the structures of compounds and materials.  

CHAIR-ELECT 2022/CHAIR 2023: Wenqian Xu
CHAIR-ELECT 2023/CHAIR 2024: Daniel Olds
PAST CHAIR: Jared M. Allred


Past Officers:
CHAIR 2021: Cheng Li
Powder SIG Bylaws/Constitution/Governing Documents
Powder SIG Reports (Members Only)


Service SIG

The purpose of the Service SIG is to further the advancement of all aspects of the application of service crystallographic techniques and to promote communication between persons interested in such techniques and results.  We are a group of friendly, supportive colleagues and a great resource in questions related to service crystallography and beyond.   

CHAIR 2023: Dan Decato
CHAIR-ELECT 2023/CHAIR 2024: Josh Chen 
SECRETARY-TREASURER 2022-2023: Toby John Woods


Past Officers:
CHAIR 2022: Ed Eng 
Service SIG Bylaws/Constitution/Governing Documents
Service SIG Reports (Members Only)


Small Angle Scattering SIG

The SAS SIG represents the small angle scattering community to advance SAS techniques and facilitate communication among researchers.  These techniques utilize both neutron and X-ray source to extract structural and dynamic information for materials and macromolecules.  

CHAIR 2023: Suzette Pabit
CHAIR-ELECT 2023/CHAIR 2024: Ruipeng Li
SECRETARY-TREASURER 2021-2023: Thomas Fitzgibbons


Past Officers:
CHAIR 2022: Thomas Grant
Small Angle Scattering SIG Bylaws/Constitution/Governing Documents
Small Angle Scattering SIG Reports (Members Only)


Small Molecules SIG

The Small Molecules SIG promotes and and all applications of crystallographic techniques to the determination, analysis and presentation of structures of small molecules.  This group is very active in sponsoring scientific sessions that focus on cutting edge areas of small molecule discovery and application.

CHAIR 2023: Brian Patrick
CHAIR-ELECT 2023/CHAIR 2024: Veronica Carta
SECRETARY-TREASURER 2023-2024: Lauren Depue


Past Officers:
CHAIR 2022: Diane Dickie
SECRETARY-TREASURER 2021-2022: Stacey Smith
Small Molecules SIG Bylaws/Constitution/Governing Documents
Small Molecule SIG Reports (Members Only)



Young Scientist Interest Group (YSIG)

The YSIG addresses the needs and concerns of students, graduate students and post-doctoral fellows who are making the transition from education to the workplace or research establishments.  Those early on in their careers will find an abundance of resources for networking, job opportunities and exchange ideas and research techniques.  

CHAIR 2023: Alexander Erickson
CHAIR-ELECT 2023/CHAIR 2024: Niko Vlahakis
SECRETARY-TREASURER 2023-2024: Kristofer Gonzalez-DeWhitt


Past Officers:
CHAIR 2022: Kenneth Childers
SECRETARY-TREASURER 2023-2024: Kristofer Gonzalez-DeWhitt
YSIG Bylaws/Constitution/Governing Documents
YSIG Reports (Members Only)